I do the same thing. I play with a group of friends, who all pay five dollars each. I usually win, but we pay second and third place so I get around $20 to $30 depending on how many people play. We play with at least 7 or 8 people, but we've had two full tables going on some games.

I'm not the gambling type at all, but I can afford to lose five dollars once every week or two, especially when there's a chance dictated by a certain degree of skill (as opposed to just dumb luck) to make a profit. If someone suggested that we raise the buy-in to $10, I'd probably say no. Because that's how the gambling mentality works (ie. "Well, if I spend more, I have a chance to make more in return"), and soon the buy-in would be up to a gazillion dollars per player (exaggeration).