Possibly, but quite a bit of the functionality is tied into the activation of the phone. Yes, the phone can be used as a reader (Kindle) or to play games, but any sort of app that would use the phone function even for minor things (location, etc.) would be severely limited, if not totally disabled.
I've got a Samsung Galaxy that was given to me that won't run most apps because it is not activated. I still use it as a Kindle reader and to run limited apps and games, but some apps I would like to use just won't run.
There are some tablets that are small that go for less than $100. I would get one of those instead. Whatever course you choose, good luck! 73.