When it comes to saving money, sometimes all you have to do is ask.
Sometimes when you contact the maker of a product, not only will they give you a sample, they'll also give you some high-value coupons. For example, we got some baby formula simply by asking for it. Similac gave us a newborn feeding kit with two packs of infant formula -- roughly a $40 value. On top of it, we got another 25 bucks in coupons.
Another thing - if you're unhappy with a product, you can let the makers know. Don't settle for a mistake. Send customer service an e-mail and chances are you'll get more than enough in return to make up for your loss.
Also - check out the company's Facebook page - often just by liking it, you can grab more coupons.
Finally, there are even websites that track all those freebies and samples: