I have two kindles one is the very basic one, and the other is a kindle fire.
I use both of them a lot, for the basic on I bought a light on Amazon which only cost me a couple of pounds plus p&p which I thought a good deal - so much so that I bought a similar one for my daughter to use with her kindle.
Well it was cheaper than buying her the kindle that lit up! Seriously though, kindle books are cheaper to buy I've found and they don't take up space on bookshelves. I also use the kindle fire much as a tablet I check e-mail and play games and can checkout answerbank, at the moment it's my favourite toy.