EDIT: Wow. That didn't last very long. Try this link from last September instead, as it's still working.
EDIT 2: I've replaced the link below with yet another one that should be working.
Walmart gave away some of these free Always Infinity pads a few months back, but this is a new link so it should allow you to sign up for a second freebie. I've sat here for ten minutes trying to think of something witty, but I can't focus since my dogs have been barking the entire time. Either they feel threatened by the rustling trees outside or this is the first stage in the inevitable coup d'état I know they're planning.