Although I have a Sony and love it, and would never buy a Kindle for myself, I've always recommended Kindles in these situations.
The ease of use cannot be beat (although I have a problem with the whole walled garden philosophy).
Although if you're going to be putting the books on, pretty much all ebook readers are easy to use for reading. Pick a book, read it.
It's getting the books on that's not so simple with other readers.
This is the lowest price I've seen on an e-ink reader
http://www.walmart.com/ip/Sony-Reade...undle/12425705
Now, it's the PRS-300 so it doesn't have a touchscreen, but pushing a button is pretty simple.