Ok this is my take on this but everyone has their own style.
Sign Up w/all the main companies that you buy from and like - most have newsletters, etc. and when they have any samples/coupons, in store events they will notify you.
Google Search: Free Samples, Samples, etc. U get the picture..
Walmart always has great samples and they do come quite quick if you are starting out.
Of Course: Keep looking on this sight.
Enter Sweepstakes - You'd be suprised many real people win them and later they send you emails on their producst.
Well not to waste everyone's time this was just to help those that are newer to all this. Hope this gives you an abbreviated version on how this all works. Enjoy the great samples, fun, games, etc.