HP-21S - Is it a rarity?

[ElectroDuende]

It is quite scarce, yes. Anyway, you can find it in Ebay from time to time, at very uneven prices... the one that is now on auction starts at 99 (quite optimistic, I'm afraid), but if you look for ended auctions, you will find some sold at twenty-something.

I got mine, a very well preserved one, but with the slip case as only accesory, for $42 + $2 of shipping, three months ago, so I consider those 43 a very good price if manual and case are included. The manual is very rare, as it is said that this calculator was sold to educational market "in bulk" without them; anyway, it is easy to find scanned copies online.

I have in my "TO-DO" list, a recreation of the even rarer guide for the use of the included programs (pretty difficult to use without it), that was a foldable sheet that can be teared from the manual, as the scanned copy has very little quatility to be printed. I promise to share.