InstaGC is a rewards site you can use to redeem instantly for Amazon gift codes (and all kinds of other gift codes). With this site, it's possible to earn money for doing all sorts of things which include short tasks, surveys, watching videos, listening to music, and more. What I love most about this one is that when you do redeem, there is NO waiting. You just ask for your code and it's there waiting for you on the next screen. It's also possible to request a check for a cash payment, but you will have to wait several days for that to show up in the mail.
Fiverr is a popular platform for offering services. You can create your own Gigs to have available for sale. As the name suggests, Gigs are available to purchase starting at $5 though you can offer upsells to increase your earnings. You do need to wait 14 days between completing a Gig to being able to withdraw your earnings by PayPal. There are fees associated with these transactions.