This is my weekend project, I wanted to build a web app with no web interface. It's ultra-MVP. It's one of those things that isn't terribly useful except when it's exactly what you need. Send a text message to a phone number, and get back the amazon.com price, new and used, with links to buy or add to your wish list. The idea is that when you are in a physical book store, you can quickly check on the price of books, without having to launch an app or web browser and without having to take a picture of the book or barcode as you have to do with some apps.

Please let me know what you think.

As a book collector and book lover (I have a web app about books, too) I really love the idea! It is great, and, as you said, it's terribly useful when it's exactly what you need. You could add to options, "AM + ISBN", which would be what you do now, and "EB + ISBN", which would give you the first three titles in eBay and the actual price, just in case :) (I am from Argentina so I won't be able to use it, but anyway, I would use it!)

Thanks for the feedback. I hadn't thought of searching other sites, but ebay seems like a no-brainer. I could add phone#'s in other countries, but it gets expensive pretty quickly (even with Twilio's low prices).

Not a bad idea. What I'd really like is an app that tells me when Amazon book prices on my wishlist drop so as that I can try and purchase them all at their cheapest.