Hi,
I have the Mighty Bright Travel Flex LED Light, the one with only one AAA Battery, and I love it. It's small but it gives absolutely enough light to read in bed and spare your spouse. You might also want to check the following threads (all in the 505 accessories part of the Forum, since at that time there was no 600 or 300 models):
https://www.mobileread.com/forums/showthread.php?t=9362
https://www.mobileread.com/forums/showthread.php?t=52447
https://www.mobileread.com/forums/showthread.php?t=26776
Have fun looking for those little accessories, it is almost as exciting as buying the reader itself