If you are a Prime member, and you’d like to get digital content such as e-books, music, and videos free, did you know you can get free credits for these things quite easily?
Provided you don’t want other items you buy shipped with 2 day shipping, the standard for Prime members, you can change this when you check out to FREE No-Rush Shipping, which delivers in 5 business days (although in my experience, the items arrive within 2-3 days max), and receive a $1 credit for digital content.
There is no limit on the number of credits you can receive, and they can mount up. Sometimes Amazon changes how they do it, but this is the usual basic offer.
You receive credits after your items have been shipped to you.