What international phone calling card has the best rates and price?

Calling Cards
justin m asked:

I live in the U.S. and I would like to make frequent calls to China…I’ve looked at a few cards but there are just so many of them….they all have some out rageous initial fee for connecting then the min. are okay but they expire….does anyone know of any good phone cards that I could purchase online?(it doesnt have to actually be a card…they can just give me an account number)…