Findbook in Taiwan creates a QR Code for the best price of a book. What's interesting here, is that they put text into the QR Code and not a weblink which could be updated.

Jump! Mobile, where I discovered this, asks what is the reason of this text QR Code.

I guess as long as there isn't a possibility to buy right from your phone, the text QR Code makes more sense than a weblink. Why? Most things we discover, we do not buy right away, but we a) either need some time to think if we really want to buy the item or b) we are not in a situation to buy (work place, cybercafé etc).
And with text in the QR Code, we don't need to access the internet, which is a big advantage for a simple reminder.

Where Jump! Mobile is right, is that this is a fairly simple use of QR Codes and it could be combined with something much more interesting. Say a best price alert service: every time the current price gets cheaper one receives an SMS. The QR Code would then look something like this: