Is an HP-10 worth $700?


As a collector, I can understand that unique HP calcs can and should command a high price. But what about something like the HP-10, which is a totally mundane item that has been replicated by many other manufacturers. First, it is not RPN, just plain algebraic. Second, it is an ordinary 4 banger with just one memory register. I own a CASIO HR-10 that does everything the HP-10 can do, plus it has a neat calendar feature, that can print out a monthly calender for any year and month that you specify and is Y2K compliant! The CASIO cost me $30 in 1982, and still works perfectly today. Its quality is excellent and it's very solidly built. Yet, if I go to TAS, I see it being sold today for $30, whereas the asking price for an HP-10 is $695. According to MoHPC, an HP-10 has already sold for as much as $400. So I ask, is the mere fact that this is a rare antique item made by the old HP make it worth so much?

Edited: 7 Oct 2009, 11:30 p.m.



Consider that even a TI-59 (!) sometimes goes for more than 100 Euros these days.




No, it is not worth so much.

The reason for such high prices is an "ebay-market" that went out of control. Sellors have noticed that some collectors may pay high prices. Now prices are generally high and most buyers seem to have accepted this state.

That's why I have stopped collecting.


There is the old adage that something is worth the sum that both the buyer and seller agree on. So for this sale we will have to wait and see ...

Even so, one can only establish a general value of a particular commodity based on a history of transactions. That is the beauty of eB**, because it gives a both a wider market exposure, and a larger number of comparative sales, than ever existed before it came into being.

Many here lament the way eB** has elevated the price of certain items, like the HP 10. However, don't forget that it has had the opposite effect on other items that sellers have flooded eB** with.


The dynamic aspect of price is important. It's the main reason that value is so difficult to assign. Markets are only rarely if ever efficient at indicating value, and no one really knows when, only when the inefficiencies have swung in their favor to some degree.

The number of items like this is far to small to hope for market efficiency. I think this has allowed a few sellers to somewhat 'corner the market', such as it is. The existence of collectors may make their actions profitable for a time, but it's hard to say for how long or for which items. I have a use for a big memory card for my 48gx, but I may just buy a 50g for much less because sellers think the HP 1MB cards, and even inferior ones, are 'collectible', making a big deal out of "the original box" and so on. Down the road a bit I have my doubts.



Not finding an 1MB card with an acceptable price for my HP48 was the main reason why I finally switched to an HP50.

For less money I got a completely new calculator with more memory than I will ever need, with easy file transfers and with an updated system.

+- 10 years ago I bought a used 1 MB card for +- 100$. At that time I think that the price was more than reasonable because the HP48 was still in production. But nowadays?


Yes. I've become quite obsessive about this. I was able to see quite a lot of Oliver Klotz's eBay feedback and figure that he ran out of the cards he built in early 2007, and I think that would have been near his price for a big card. I also noticed that his card business really came to a halt over the previous year, so it's understandable that he quit.

BTW - I just ordered a 50g new for £113 -- and I know it goes for the same number of dollars, but with VAT/duty and shipping it comes out to the same thing!



I usually set, as the *upper* limit on the amount I'd possibly consider paying, the inflation-adjusted price of the calculator when it was introduced. This philosophy is based on the wish (sometimes) to be able to go back in time and buy the desired item new. Generally, I'd consider paying something near this only if the item were in like-new condition, with all accessories and documentation in likewise new condition.

For example, the most intriguing HP calculators to me are:

HP-29C - $195 in 1977 ($695 in 2009)

HP-34C - $150 in 1979 ($446 in 2009)

HP-15C - $135 in 1982 ($302 in 2009)

HP 42S - $120 in 1988 ($219 in 2009)

The HP-29C and HP-34C would be overpriced by this process, while the HP 42S would be a minor bargain.

The HP-10 was $175 in 1977, which was equivalent in buying power to $624 in 2009. By this process, $700 is not so far off after all. I personally wouldn't pay such an amount, if for no other reason than I considered the HP-10 to be a very boring machine when it first appeared, and I still do today, regardless of how rare it is.

Edited: 8 Oct 2009, 5:30 p.m.


I bought my HP-15C in 1982 for $108, and it still works perfectly today on only its third set of batteries. I still use it a lot and it is one of my favorite calcs.

I bought an HP-34C in 1979 for $123, and sold it to a co-worker when I bought the HP-15C. Two years ago, I bought another HP-34C complete with all accessories for $95, that was in good working condition but needed some case repair.

I just picked up an immaculate HP-29C that works perfectly for $385. It included only the soft zipper case and Quick Reference Card, which were also like new. Since I already have the HP-19C/HP-29C Owner's Handbook to go with my HP-19C, I basically have a complete set.

I have never owned an HP 42S, although I do have FREE42.

I have no interest in owning an HP-10, even for much less than its inflated value. Like you, I find it to be totally mundane.


I have never owned an HP 42S, although I do have FREE42. must correct that!

Many people (I'm one) consider the HP 42S to be the best RPN calculator ever made, even today 21 years after its introduction. It's not perfect, but perfection's peak can be seen from it.


I suppose it's all because of the path I took as opposed to others in my progression through HP calculators. I moved from the HP-34C and HP-15C straight to the RPL calcs, bypassing the HP-41. Since the HP-42S is HP-41 compatible, rather than RPL, I never saw any need to buy one. I've owned an HP-28C (1987), HP-28S (1988), HP-48SX (1990) and HP-50g (2009). I still have all of them, except the HP-28C (sold it), and the HP-28S is sidelined with a broken case at the battery door. Given the current feeding frenzy for the HP-42S on TAS, I've not seen fit to pay the prices currently being asked. Also, from the collection vantage point, my main interest is in older LED calcs like the HP-29C that I paid so much for. I would never pay that kind of money for an HP-42S or something like an HP-10C.


The trail of HP-29C to HP-34C to HP-15C to HP 42S was a logical progression through four generations in capability, sophistication, and decreased price for all-in-one-case (no expansion) RPN calculators, from 1977 to 1988. It would have been wonderful had this progression continued with two or three later generations between 1988 and 2009.

But such was not to be, and the HP 42S has remained the best-in-class for more than two decades. Its capabilities are yet so useful that most by far who pay those high eBay prices seem to be doing so not to acquire some collector's piece, but to have the best small RPN calculator that HP has ever made for actual work use.

I used an HP-15C as my day-to-day calc for ten years, so I didn't know I wanted/needed an HP 42S before they were discontinued in 1995. I was very fortunate in 1997 to find two new-in-box HP 42S units priced at $114 each still unsold after four years on the shelf at the University of Alabama at Huntsville bookstore. Although I had used the HP-35, -45, -67, -21, -41C, -41CX, -15C, 28C, 28S, 48SX, 48GX, and 32SII, I found the HP 42S to be simply stunning in its capability and ease of use. It has an excellent alphanumeric human interface, especially compared to the HP-15C that it replaced. It remains my favorite, though my HP 50g RPL machine has some very good points too. I usually take both with me to work, sometimes with the financial brother of the 42S, the 17BII.

The auction prices of the HP 42S seem to have moderated a bit with the recession. I think there are about five on ebay at any given time. I'd go after one if I didn't have my two. A calculator this good, this important, deserves to be part of any HP collection.

Edited: 9 Oct 2009, 12:59 a.m.


As if to illustrate my point about lowering auction prices on HP 42S units, here is an auction that finished a few hours ago for an HP 42S, an HP 82240B printer, and original spiral bound manuals. For $183! That's well below the inflation adjusted price of the HP 42S alone.



I have never owned an HP 42S, although I do have FREE42.

I have no interest in owning an HP-10, even for much less than its inflated value. Like you, I find it to be totally mundane.

Interesting, how different people sharing the same hobby can be ;-)

I would have phrased those two sentences as follows:

"I have never owned an HP 42S and am even less interested in emulated calculators."

"I have no interest in owning an HP 42S, even for much less than its inflated value. Like no-one else here (?), I find it to be one of those dull 1980s mass produced grey LCD calculators that does not invoke the slightes desire in my fingertips to ever touch one of its keys, even less to navigate through one of its menus..."

And regarding the HP-10: It is one of the two most un-typical HP calculators and no collection will ever be complete without one. And it if you ever show your collection to a non-HP-enthusiast, it probably will be one of the three items immediately picked out by him (or her). Because it is so different.
My personal price limit would be something like 200 Euros though. It really isn't worth more than that - even considering its rarity. And with patience, you can find it for that amount - even on the bad evil horrible auction site (at least I did).

Greetings, Max


First, it is not RPN, just plain algebraic.

A small correction: it actually has "adding machine" logic, which is a combination of RPN for addition/subtraction, and algebraic for multiplication/division.


A small correction: it actually has "adding machine" logic, which is a combination of RPN for addition/subtraction, and algebraic for multiplication/division.

Correction acknowledged, however, I still say this is nothing extraordinary or unique to HP; my $30 CASIO HR-10 printing calc works exactly the same way. In fact, I have a $1 "Big Display" calc I bought at Walmart for kitchen use that works this way and has memory arithmetic plus square root.


Hola Michael…

A lot of Money for such a simple calculator, I agree… but let’s see how it ends in a coulple of days...

The price of a piece of a collection, I think, is not so related to the quality of that piece. Once you’ve decided that it has to be part of your collection, the price is related to the how-difficult-is-to-find situation, compared with the rest. This involves also the other stuff supposed to arrive together (manual, case, etc).

I won’t put the present value of the (those days) new price as a limit because an HP 65 could be as expensive as 3,500 USD nowadays, following this rule…

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