If you can traverse the lock issue, T-mobile has a prepay plan that costs $3.00 per month and includes 30minutes of call time in that charge. Additional minutes 10 cents each.
I found the plan online tucked in some corner of T-mobile's sprawling, jumbled web thang and took the url to the store with me. The smurfs there disavowed any knowlege and tried to move straight to the upsell script, which is where having the url of the offer came in.
They had to use their magic store codes to push it all through the servers and take my money, I would cheerfully pay a dollar extra not to have to deal with a call center anytime, but did not have to.
Phone service works fine --no complaints for last three years.