Ok, it sounds hokey, but I troll around all over the internet for free stuff, coupons, whatever....
A few sites I really like (because I just cashed in on both of them) are swagbucks and epoll. Epoll is a survey system, they send you survey links via email and you build up points for each survey you take. I've just ordered a $10 amazon certificate with my points, so it works well, but the points take a while to build up. Since it's all email-based though, it's really worth it.
Swagbucks is a big thing right now, and the $5 amazon certificates are really easy to get. You should be able to get about one a month, but I haven't been that lucritive yet.
It's sad, but I also troll for online giveaways and such. I did actually win a workout DVD from sparkpeople earlier this year, but I think that's the only thing I've ever won! Sometimes it feels so dirty, selling out my email address for a chance at free stuff, but I've found a lot of sites I really love. Sparkpeople is quirky, but they have some great articles, motivation, and a really interesting blog. Check it out sometime.