Right. I can read my Kindle for hours on end without it hurting my eyes. I have the newest version of Kindle, the very inexpensive one with the ads. It is only $79 USD from Amazon. It is just like a book -- if you're reading in the dark you have you use a book light.
The new Kindle tablet, the Kindle Fire, IS backlit, so if the non-backlit thing is important to you (and if you do a lot of reading, it probably will be) then stay away from that model. On the other hand, if you're looking for a tablet it is very inexpensive (for what it is) and can do most of the fun stuff that other tablets can.