Want some free Facebook Advertising credits? All you have to do is search for it!
Look for the keyword “fb coupon” on http://www.google.com and you will many places where you can get $50 ad credits and even more. Another awesome place to search is http://search.twitter.com. Also try http://www.ebay.com where you can find people selling Facebook ad credits.
Important: Once you bought the coupons, do note that you can only use 1 coupon for 1 account only. Don’t buy 100 x $50 coupons and think that you can use coupons all the way for your FB campaigns. Facebook is not stupid.