If you're not using Swagbucks as a search engine, I can't imagine why not. It's free to use, simple, and you end up with some really nice little treats as a bonus just for doing your regular searches online.
I usually go for the Starbucks cards and the Amazon codes because I know I can use them in Canada. If you're in the States, there are lots more prizes available. There are lots more for Canada as well, btw, those are just the ones I like!
It's a nice little luxury for me to get a Starbucks card in the mail - I love their drinks but usually have guilt over spending the money. The card lets me treat myself and my husband, guilt-free.
How does Swagbucks work? Well, you sign up (free), and simply use their site to do your searches instead of Google or whatever. Random searches are rewarded with varying amounts of Swagbucks, and the Swagbucks add up until you can redeem them for prizes. You can also download the toolbar. I have the toolbar for Firefox on my Mac, and find it easier to use than remembering to hit the site for searches.
You can earn even more Swagbucks if you pay a little attention; they release codes on their Twitter, blog, and Facebook, as well as on the toolbar. (I usually miss those because I forget to look.) The numbers add up pretty fast if you just use it to search.
Anyway, if you decide to sign up, I'd be honoured if you'd use my referral link. I know some bloggers have a zillion referrals to SB - I don't - but I'd love some more.