American Airlines offers 100 AAdvantage miles
when you "Like" its Summer Miles Challenge
on Facebook and submit your name and email. That's the best freebie offer we've seen from American Airlines since February, when we saw 1,000 miles for free. (We've seen 2,500 free miles as recently as today, but they require you to activate a paid Netflix subscription.) The miles will be credited to your account six to eight weeks after the end of the promotion.