It sounds like most of the posters here either strongly favor gambling or don't like playing for stakes much at all. I'm different in that I enjoy playing pool about equally either way, although I will say when I gamble it usually is for small amounts. About $5 per game (8-ball) or $20-$30 for races to 4 is my norm, and the most I ever wagered on a single game was $100.
I do get a different kind of enjoyment from playing depending on whether it is for free or for money, though, and it depends on who I am playing with. There are guys I know that I won't gamble with even though I usually have the better of it with them. They take it (and themselves) way too seriously when gambling, and their foul mood ruins the experience for me. There are also guys who I will only gamble with because without something on the line they don't care enough to give me their A game.
When I'm not playing for money the games are usually more social, with more conversation and teaching/learning opportunities. I don't include playing for a beer/drink as gambling in these scenarios as we would most likely be buying each other drinks anyway. Sometimes these free sessions can be quite competitive, too, and I find that I can focus just as well in these as when I am gambling. Bragging rights can be just as big a motivator as money as far as I am concerned.