Update: Apparently you have to make a purchase first to get the $5 credit

This one is valid on NEW accounts only.

Sign up with this link and create a new account. For joining with that link you will get $5 just for creating your account. After you get a verification email you should be able to get your $5. (Takes a little time for it to go through).

There are certain places that offer gift cards for $5, like Starbucks. Should get you a completely free gift card!

You can also get a free $5 gift card at Cardpool and Free $5 Gift Card from CardCash.