Ways to convert Amazon gift card balance to cash / make money shopping for others?

So, I guess this is a two part question.

What are ways to convert a gift card balance (redeemed) to cash relatively easily? Are there any virtual things that can be bought and resold on Amazon or another site with a gift card?

I remember seeing a site where you can buy things for other people on Amazon, and get paid for it. I'm not sure how legit this was but I would love to find it again.