I buy my 3S 2200mAh packs from Heads Up RC. Usually about 16-20 USD a piece and flat rate shipping of 2 USD.
In general, when it cones to lipos: The quality of the pack is directly related to the price you pay.
Rating
u RC batteries from Hobby King by: Matt
I've had quite a bit of success with buying cheap lipo batteries from Hobby King. In fact that's where I buy most all of my batteries.
Of the many that I've purchased there have been 2 or 3 battery packs that arrived with a bad cell. You know immediately when you tried to charge them the first time. Kind of a bummer.
But the amount I have saved over buying popular name brand lipo battery packs has exceeded the cost of those few bad ones many times over.
I also like that Hobby King's website has user reviews for each battery. Folks often will describe which aircraft they used the batteries in and how well it worked out for them. That helps me with determining which lipo back to go with.