Amazon is still running their Amazon Cash promo. As the name suggests, it's a way for you to turn cash into Amazon credit at over 30,000 participating retail locations. While that might seem counter intuitive to some, I know there are people out there like yours truly who tend to spend cash in my pocket far faster than if I put it in the bank or have it as store credit.
Since people love free money, they're offering $5 in free Amazon credit to new users when you add $20 to your account thru 3/31/21! Simply generate a barcode by clicking the “Get Your Barcode” near the top left. Then either print it out or send it to your phone via text and visit a participating merchant like CVS, Gamestop, 7-Eleven or a dozen more stores. You'll then pay $20 in cash and have the store scan your barcode, which will give you $25 Amazon credit!
So in effect, you pay $20 and get $25 in Amazon credit! You can then go online immediately and spend the credit on anything Amazon sells.
The free promotional credit expires 4/30/21, so make sure you to redeem it before then.