When I was looking for a PAYG Samsung A800, I trawled the net for AGES looking for the best price and eventually found that the cheapest place by about £20 was actually Virgin! This included a free sim-card and airtime vouchers.
Ok, so you have to put up with a tiny little Virgin Mobile logo on the phone, but it was a bargain. (I`m with Virgin so it didn`t matter!)
Big A
I let my mind wander....and it didn`t come back.