Working Amazon Appstore APK
For some HTC Ones on AT&T the current version of the Amazon Appstore will not run. I had this problem and some others have as well. This may be a problem with all HTC Ones or just some.
I found a copy of the apk in my backups from October 2012 that works on mine.
Click here to download the apk
Current: AT&T LG Optimus G Pro
Others: T-Mobile G1, Motorola Backflip, HTC Inspire 4G, Samsung GS II i9100