With servos like anything else you get what you pay for, I'd save some more money to get a high qaulity Dig MG High Torque jobber like a JR or Hitec. But if your absolute on getting something cheap heres a option.
http://www.hobbypartz.com/radm49gdisew.html
You can alwasy pick up something on Ebay cheap but your guess is as good as mine on what youll actually receive ?