My Kindle (the $79 version) is Wi Fi. It operates off of our home network.
It is the least expensive of the Kindles. It doesn't have a touch screen, so you have to use the "buttons" on the sides of the Kindle. Project Gutenberg and Amazon are both good sources of FREE books - if you like the classics. Amazon will occasionally have an "e-sale" and discount certain books a lot.
The electrostatic ink (E ink) gives you a clear, crisp display. It will display advertisements on the screen before starting.
If I were to do it over again, I'd consider one or two models up - the Kindle Touch or the Kindle Touch 3G. As it is an E reader, I don't know if I would consider a keypad version. I'm not using it as a tablet - just a reader.