Just like previous, similar deals, this deal excludes Kindle titles and audiobooks, but if there are any commemorative coffee table-type books or collector’s editions that you’ve been eyeing, this is a great opportunity. Just choose carefully; you can only use the code once per Amazon account.
You can buy multiple books to meet the $20 threshold, but here are a few $20+ suggestions to get you started. Again, this works on any physical book Amazon sells (shipped and sold by Amazon directly), so you shouldn’t have any trouble finding a use for it. Let us know in the comments what you got!