I've been watching Ebay for a while, and prices always seem to be much higher than I had thought. I also never see less than perfect Curtas (by the look of the images - I'm definitely not a good judge of these things). Will prices go down again at some point?

What I really want is a calculator I can actually use, not a museum piece. It doesn't need a case, I don't mind discoloring or chipped paint, but preferably all pieces there. What is the cheapest one of these might go for (I was hoping for something under £800 - is this completely unreasonable)?

I've never owned one, so any advice would be appreciated. Are there any sites other than Ebay which I should look at? Does anyone here have a calculator that they would be willing to part with? What have prices been doing? Should I just stick with slide rules?