Ixamyakxim: It's not GoG - a lot of these VISA gift / prepaid cards (and in fact all of the prepaid "credit" cards) actually have a disclaimer in that tiny print on the back, that no one ever reads, that says "For Domestic Use Only..." So no go on Gog :(
This. Some US lobbyist tooting "terrorists" use them, got a stupid law passes making US giftcards only work with US billing address businesses.
Since gog billing is Poland, all giftcards shouldn't work. Even if you use it with paypal (at least I have not figured out how to use us giftcard internationally through paypal).
You can maybe find a nice gog trader here in the forums to trade with. The nice traders do it $:$, not not try to make a profit (you can personal message me if you want to try working something out).
Ps. you should be able to use your US giftcard at amazon.com and @ steam.
<<<this reminds me, when gog tried their 'regional pricing' I bet gog still didn't have a billing address for each f'n region. To enforce regional pricing, you must have a billing address for each region, unless gog was trying to do something unscrupulous>>>