The stuff that I wanted was free in the Amazon store, and my wife is finding all the free games she wants to try.
You can get a lot more stuff in the "Market", but I found that a lot of those apps were made to run on phones, and didn't work very well on the Coby.
The email, facebook etc work okay, and we really haven't looked for much of anything else.
The Fire is a reader, and you can go anywhere there is free wifi and download books..
Even free books, if you don't mind them being very old..
I used my Coby to link into my CAI controller board, via an old WiFi router (stand-alone).
I was thinking of using a tablet as my I/O console for the CAI, but I will likely
just use one of my old desk top PCs downstairs.