Can I use my iphone purely as a camera without paying for minutes used?

Can I use my iphone purely as a camera without paying for minutes used? - 1

Yes, just turn off the wireless network connection. You can still use wi-fi, bluetooth, etc (turn them on/off individually). Essentially, you just use it like an iPod Touch.

The minutes are for calling/talking on the phone, not the camera. The camera should still work regardless of having minutes or not. Camera should not use minutes.

Well yes. The camera has nothing to do with the minutes you used.
You can take a thousand pictures, and you won't use a single minute.
Now, if you have iCloud on, your phone may upload the pictures you take to the cloud, which may use your cellular data, so turn that off if you don't need it.