Naturally, I contacted Amazon last night. Also naturally, I got a simple form letter back. The following is a quote from them.
I'm sorry to hear that three titles for $15.49 and one for $11.49 is listed "Under $10" in website promotion page.Yeah, blah, blah, blah. All they do is copy/paste some of what I said into their form letter and send it off.
We use many sources to build our website information, and we really appreciate knowing about any errors which find their way into our catalog. I'll notify our catalog team about this and will ask them to correct the error.
Please know that we value your opinion and will continue to listen and respond to our customers' concerns.
It is because of customer comments like yours that we...
In any case, at least they mentioned my complaint, which most do NOT do. That's something anyway.