Welcome sun4384!!
You've gotten some good advice here. As Desert Grandma says there are a lot of great public domain books here at this site that are specifically formatted for both the Kindle and the Sony.
A couple things to consider--the Sony doesn't have any wi-fi access. This could be a good thing if giving this to your son. You could load it up with books and wouldn't have to worry about him finding a way to download stuff you'd rather he not have/see.
I have a Sony (love it) and it seems fairly sturdily built. The frame is metal as opposed to the Kindle's being plastic. But, the screen is the fragile part and I'd be uncomfortable giving my Sony to my eight year old niece.
The Sony is considerably more expensive than a wi-fi only Kindle ($229 compared to $139) so that's another consideration.
Good luck making your decision!
dordale
