Usually I get games from the bargain bin. Hardly ever do I get brand new games. Usually, I get a game for around $10 and play the hell out of it until I get bored.
I think that this is a really interesting question. I must say that buying used games can sometimes be very profitable. I know members of my family once bought games that cost around 60 pounds or so, for about 5 pounds only. You can imagine the difference. Did I personally do it? I did before in the past and have had some issues but most of the time I haven't had any real issues with it, I could instantly replace it. There are loads on eBay though.