[Stu]

This is a PS, kind of sort of. TMobile's Hotspot at Home works with prepaid SIMs. The calls are not free. They are billed the same as if they are made on the prepaid network, but for someone trying to manage a US sim from abroad, this would give you limited access to the account/sim from your home country.

Hotspot at Home is TMobile's brandname for its UMA set up which is GSM over ISPEC, a non-SIP based form of VOIP.

Stu