I always just say "asking price $600, or whatever depending on the title. That price is what I will take minus a hundred or so. If they offer 500 I'll go 550 and then the negotiating is narrowed down. If they come in at 450 I'll say 575! Then they will usually settle back to 550 and it's a done deal! Not rocket science or anything. I don't start out with a ridiculous amount though, I come out with fair average price which I feel I'm pretty good at. I feel most people are, but some people think everything they have is worth premium pricing. And I hate it when people want to 'just get what they have into it'...

Well if you have 2k into a game worth 1k that's you're problem...
Try selling a car worth 5k for 8k and say well It has new tires new exhaust new stereo, recent valve job whatever, you're not going to get back everything you put into it!!! It's still a 5k car at the end of the day!

Tom