Gap is teaming up with Facebook to give its fans some free stuff. Well, lots of free stuff. Today, Facebook announced at its mobile event in Palo Alto, Calif. that the specialty retailer would give away a pair of jeans to the first 10,000 people who checked in on an upcoming day. (The specific date has yet to be disclosed.) Those who check in after the first 10,000 will receive 40% off a pair of jeans.

This is part of Facebook’s new “deals” program, which works a lot like Foursquare’s “deals” program. Checking into Facebook via your mobile phone will soon mean getting discounts at many of the shops you’re visiting.