And here's the kicker... they consider this an AUTHORIZED TRANSACTION! They will cancel if you call, but here's what happened. I found this link, and I don't even need to retype it all, because it is exactly what must have happened to me.
LESSON LEARNED: Don't click on those "Click here for $20 rebate!" pop ups... as soon as you do, all of your personal information is transferred from the website (from which you're buying legitimate stuff) to some organization called "Great Fun", who charges you a "membership fee" of $12.99.