I was going to say that I spend under $100 in a year, but I started doing the math, and it seems to be even lower than that. Off the top of my head I can name 40 some-odd dollars worth of PC games in the last year. Since most of them came from thrift shops and steam sales, I bought a lot more games than that would imply -- come to think of it, I haven't paid full price for any games this year, even though I bought a few of them new at retail. I know I also bought a couple of PS2 games from the under $10 bin at Gamestop, but I think I'm safely under $70 for the year so far.
The funny part is, I had a job for the better part of the year, which means I've probably spent more this year than I do on average. I imagine if you add the books, CDs, Records, Cassette Tapes, VHS tapes, DVDs, and movie tickets I've bought this year, you'd see a much higher entertainment budget. Might be fun to work that out sometime.
Edit: Forgot that I dropped $20 on a used copy of F.E.A.R. this year, putting my PC purchases closer to $60. I still think I'm under $100 on directly gaming related purchases, but It wouldn't surprise me if I break $100 some time in the next few months.