Get a free sample
of gingivitis-fighting Crest toothpaste courtesy of Walmart when you answer two questions about your teeth. If you don't appear to have gingivitis, Crest will send you a sample of another type of toothpaste. Share your name, address, e-mail, and birth year, then answer three quick questions about your toothpaste habits. You can opt in or out of Walmart's e-mail newsletter.
This freebie already ran out once, so I don't expect it to last long.
Caveats: while supplies last. Give your free sample a few weeks to arrive.