Sure you can do that, but I wouldn't suggest it more than once. If you frequently buy/sell between the same accounts, then this will be noticed by Amazon as something very unusual and they could block both of your accounts. I do what you're suggesting, but I only do it once and I do it as a means of buying something small and giving my new stealth account some quick feedback. I'd never buy from a stealth account several times with the same account. That would certainly raise a few eyebrows. If you have $10 on your gift card, just use it. Go to Burger King or something. If it's a little more, order a pizza one day when you're hungry. To me, finding cards laying around with $10 or $15 on them is like finding money under the couch.
If you don't like this idea, then get your card for a specific amount, like $50. After you verify your stealth amazon account with it, just open a bank account online. Most bank accounts can be open with $25, so deposit everything left on your card into that account when you open it...boom, new checking account with $50 in it. Another way you could deal with this problem would be to just search the marketplace here and buy ccvs. They are cheaper and only have $1 on them, so you will get to verify your Amazon and not worry about having to deal with all this money left on your card.
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