What is the ruling on purchasing a Visa card from an individual, not a bank, prepared for making purchases from Amazon, in exchange for a check that will be cashed after a few days?

Prepaid cards that hold a balance in one currency and are sold in another currency are considered a currency exchange contract, and require actual or constructive possession. Examples of constructive possession include: a bank entry of a sum of money into the customer's account, and purchasing the card with a certified check or a cashier's check. A regular check, however, is not considered constructive possession.