I have a Pandigital Supernova and just love it!!!!
It uses the Barnes and Noble store. But can also get Apps from
the Amazon appstore. and did download the Kindle app. although
I have not use it yet.
Most of the time I just use the B&N site.... but there are times that
I will be looking for a book and it won't be on B&N and go to Amazon
and it will be there.
When you look for books just type in Free Kindle books in the search box.
That is what I do on B&N but change the word to Nook.
There are also 2 Apps that you might like.... Or any one else too
Olive tree bible
Bible.Is --- This one will actually show video of Bible stories