Just used a booklight with my Kindle for the first time since I've owned my Kindle (about a year). As someone else mentioned on the forum, it's pretty easy to read the Kindle in low light ... but not no light.
Luckily, I'd just picked up an inexpensive booklight by Energizer for $7 at Target. For reference, I'm including the link to the same light on Amazon:
http://www.amazon.com/EVEFNL2BU1CS-R.../dp/B000GOYMAE.
I found this light worked very well - as well as being inexpensive.