I don't really think I have a max to be honest. However, to me a big part of the fun in collecting is finding a good deal. It makes me feel better about a piece if I hold off on buying something for a couple of weeks just to find it at a cheaper price. That being said, if I really want something I'll just pay for it. I don't really know what the most is that I've spent on a single game. Probably somewhere around $150. I buy a lot of new titles so spending about $110-$120 is pretty common for me (collector's edition game + collector's edition guide).