[GadgetKen]

It looks like they charge a daily fee for an inbound US number so this probably wouldn't be a good deal for an occassional international traveler. Maybe the Estonia only card paired with a third-party call forwarding service would be a better deal.:

"Phone number activation requires some payment obligations to be met: one-time payment of activation fee and monthly charge.

Monthly charge (for the 1st month) will be deducted from the account after you activate the number (together with activation fee). After 1 month expires the deductions will be automatic and take place every day based on equal daily increments according to the number of days in a month (1 day = 24 hours).

Example for US based number: Activation and the 1st month of using the service will cost: $9+$5=$14. After 1st month the deductions will take place every day and make up to $5/30 = $0.17 daily. After the funds in the account have been exhausted to pay for the activated phone number your personal telephone number will stay reserved for you for the length of two weeks (14days). After two weeks passed the number will be canceled and returned to our database."