EDIT: Aww, they're gone.
You can sign up for three free Tampax Pearl tampons after liking them on Facebook (your friends should love that). This is part of their Tampax Tuesday campaign. I bet you didn't know that existed.
The confirmation page will say “You sample…should arrive at your provided address in four to six weeks.” That's a good place for it to arrive. Where do other freebies usually go?