Not seeking to contradict you, *but* I've also seen a couple of the games you mention go for under $10 complete in box. In fact, I bought one of them myself for a few dollars.
No offense taken
I'am checking the Amiga/C64 game market regulary for only a few weeks, two months at best. By now i've already seen Apidya go pretty cheap (30 Euros), but at least on the german market its very rare.
Sometimes people also just ask for insane prices - i just spotted a C64 in working condition with a minimum of perihperals in bundle, and the guy wants 1000€ for it; Well - good luck with that XD
As Franko linked, the UK market appears to be very different, for example. Lots of games that go for 1 - 7 Pounds there would be sold for at least twice the price on the german market, some even pretty expensive. If you find a collector who is willing to pay, that is
- Gil