I'm not sure T-mo have plans anymore, like ATT and others, phone is charged separately, specific amount for specific time, but to make sure just
go to T-mo website and choose "bring your own device" plan, or check with local store, they may have something not announced etc. Also check if you qualify for corporate discount.
go to T-mo website and choose "bring your own device" plan, or check with local store, they may have something not announced etc. Also check if you qualify for corporate discount.