The price of Curtas seems to have gone up over the past 18 months. eBay has plenty of listings for Curta I and IIs, but you'd have to shell out more than US$1000 for one, unless the unit was in bad condition.
What first piqued my interest in them was a watch and clock show in my town. I remember really thinking they were marvelous engineering, but I also remember that number of $1000 as an average for a working one.
However it's kinda iffy buying one that you can't actually test first. It's been too long since I've purchased anything on eBay so I don't know what the return policies are.
The guy at the show mentioned "always test the _one_ slider. Those go first"
eBay leaves the return policies to the individual sellers, so some sellers absorb the cost of returns, some require you to pay postage, and some don't accept returns at all. Naturally some of this probably gets absorbed into the listing price.
However it's kinda iffy buying one that you can't actually test first. It's been too long since I've purchased anything on eBay so I don't know what the return policies are.
The guy at the show mentioned "always test the _one_ slider. Those go first"
Edit- spelling