You need to update to ios 7.0.1 it has a fix for that problem.
Answering because I solved the problem - at least for me.
I went into Settings -> General -> Reset
I reset all settings (*not* content)
I had to re-enter a few passwords and such after the restart but the sensor worked for the App stores.
I suspect that coming from the developer beta there was seem crap left in or changed in the release version and when I restored from backup it didn't correctly setup the sensor and/or stores.
(Technically, I also swapped iTunes accounts in here, tried a US one and then CAN one just in case it wasn't the reset alone).
Simple solution. You must first log into the iTunes Store. Once you have done that, you will see that the iTunes option is no longer grayed out in the fingerprint section.
Answering because I solved the problem - at least for me.
I went into Settings -> General -> Reset
I reset all settings (*not* content)
I had to re-enter a few passwords and such after the restart but the sensor worked for the App stores.
I suspect that coming from the developer beta there was seem crap left in or changed in the release version and when I restored from backup it didn't correctly setup the sensor and/or stores.
(Technically, I also swapped iTunes accounts in here, tried a US one and then CAN one just in case it wasn't the reset alone).
Thanks this worked for me finally! So after doing reset all settings:
1. put in a passcode.
2. re scan fingers
3. I noticed the toggle for app purchase was greyed out.
4. wen to the app store and downloaded a free app.
5. it asked for my passcode then asked if i would like to use itouch for purchases!
I'm having this same problem. As far as I can tell I have I the right settings selected.
I tried doing several free purchases to see if it would eventually ask me for fingerprint but it doesn't. I've restarted the phone, restarted the app store, even did a full restore on the phone.
I am restored from a beta GM backup if that is common to anyone else having the problem.
On 7.0.1