am3x prepaid rewards card like those sent out by companies like TCB can only be ran as credit so you can't buy MOs with them that's why you have to buy VGCs first, use them to buy MO to deposit to your bank.

buying the right kind of VGC is crucial depending on where you're buying your MOs. If you're buying MO at WM, buy the ones issued by Metabank or GreenDot Bank. If you're going to the USPS, buy the ones at the drugstore issued by Bancorp called Vanilla Visa GCs.