Wal-mart gift cards sell for almost full value on eBay. $500 cards sell for about $495. Sometimes they even sell for more than $500 because Sam's members can use them for a gas discount which makes them more valuable.

So there's no risk involved here. Either wal-mart will sell you a money order from the card or you can sell the card on eBay. You'll only be out about $2 for the listing fee.