The bid is 500? It should fly. Go as high as you can, with evidence of it going higher than the already extortionate 500 there should be plenty to put in 10 dollars to make it happen. How much are you going to initially bid?
I think 300 is fair as your base bid and fair, with the rest extra juice can come from people wanting a copy of it. Just pump heaps of money in. I doubt anyone would buy it for more than 600. Youll be compensated and have the game for yourself.