That's actually a topic I was thinking of discussing with you guys: For my videos I had to get many lots of stuff (from eBay, from leboncoin, from random places you never heard of), and I ended up with a bazillion of duplicates.
I did try to do some swaps, had limited success, hopefully Symoon, Baz and Steve are happy of the deals, but I still have many games, which I will probably have to sell.
Ideally I'd like to avoid eBay, because it's a very rigid structure, and the ebay tax on the sell is something I'd like to avoid.
Me being in Norway brings another problem: The price of the shipping is crazy (like 35 euros even for one single tape), so selling just one or two tapes makes no sense.
I refuse to enter the eBay/collector inflation game either, but I'm not going to give a way for free what I had to pay for, so it would be interested to see what people consider as fair prices.
As far as I'm concerned, "Welcome to Atmos" and "Defence Force" could almost come for free with any pack of tapes, there are so many of these around that a fair price would probably at must 1 euro.
Then we have the semi (worldwide) ubiquitous: Xenon, Zorgon, many of the early Tansoft, IJK and PSS, which I would probably prive in the 2-4 euros range.
After that we have the thing which is not rare but harder to find because it was only released in France, like the games from Loriciels, Ere Informatique, ... I guess fair prices would be around 5-10 euros range depending of the state, if the come with manuals or not, etc...
Things with heavy boxes with thick manuals, bonus materials (like the Cobra Software games that came with "physical clues", The Hobbit with the book) I'd say would be in the 10-15 range.
Some games are really hard to find, specially in complete condition, like Manic Miner (with the protection card), or the earlier adventure games (Level 9, Salamander) which I guess are acceptable in the 15 to 20 euros range.
And then there's the bazillion of limited interested, limited releases, shitty games in basic that are of only interest as a collector item for people who want full sets of something, generally they are ugly, half of them don't load properly, but they are super rare, so I guess they have a collector value of +infinite and an actual interest value of -infinite
What are you people thinking would be fair/acceptable prices for games?