Here's one option for a U.S. Citizen that does not have a US bank account, phone number or billing address that has worked in the past.
All US embassies and "most" of their satellite offices (depending on the country) have a US banking facility in them. There you can purchase a pre-paid VISA in US DOLLARS. Then register that pre-paid VISA on the internet with a valid US mailing address and a valid US phone number. (You can use the address/phone of a relative in the states maybe?) Then you can use that pre-paid VISA to purchase the TurboTax product of your choosing, and to pay any filing fees you may need to pay when you actually e-file the return.
