Check this page:
Looks like STi is the best if you don't use wireless a lot.
For example, TracFone would charge $80+ for a year's
service and 150 minutes. STi only charges $18, even if
all your calls are at weekday peak time.
In addition to their low rate, STi offer a few nice free-after-
rebate phones: Samsung A660 from Staple, LG 5225 from
STi (You need to buy a $50 card), and Sanyo 200 from
CompUSA (Now it is back to $110 minus $100 rebate).
I got a Samsung A660. This is brand new phone, quite good
looking flip color phone, that is far better looking than my old
free phone (remanufactured) from TracFone. .The reason for
Samsung is that I am more comfortable with Staple's easy rebate
I don't know how STi can make money with that kind of price.
I wish them good and be profitable, and we can have more
choices in the low cost prepaid phone market.