Cereal.com sends out weekly emails every Friday morning on how to get freebies (print out coupons, in-store giveaways, etc.). They also have some great breakfast recipes!
terrisatx has my answer: startsampling.com. My mother has used it for years; you need to check the blogs on the lower right side. Also quizpoints.com is updated daily. And www.sweepswire.com has fantastic new daily sweeps to enter.
Walmart has Free Samples, Costco also offers them. Visit sites of companies you are interested in their product. Write them some feedback, they may send you some product samples, or coupons off your next purchase.