Sort of hard to follow what's happening here, but it sounds like (with only your side of the story) you were willing to do what potential buyer #1 wasn't and actually show up with cash and buy the game. I don't see any issue unless potential buyer #1 had maybe given a deposit or had already made arrangements to pick up the game. Assuming potential buyer #1 had their fair shot at it and waited too long then have at it. Hard to make a judgement with half of the information, but if that's true then I wouldn't lose sleep over it and I definitely wouldn't be compensating someone for sleeping on a deal.