Upvote:2
Do you have an address in the US yet? Do you have a social security number? You will likely need both for a rechargeable prepaid debit card. Same for a secured credit card (ie you open an account with $500, they give you $500 credit line).
You might consider a Visa Gift Card, which can be bought and used by anyone. But if the registrar for drones is limiting registration to US based cards, they maybe able to detect a gift card and block it to avoid registrations by foreigners.