Another update:
The "issue" is now over. You can buy books again without the use of a VPN thing. I just bought one normally, and it worked.
I learned this from a recent comment on
http://www.melvinneo.com/do-life/self-help-book:
"Read in the Kindle forums that Amazon CS said it was a “technical glitch” that has been fixed. I just disconnected the VPN service and tried to purchase a Kindle book. It works now, just like pre-Friday. No more “restricted geography” message. Cheers."