Hi Book Worm and welcome to the Forum. I got a 505 a year ago and really like it. In fact, waiting for the thing to charge up was about the longest few hours of my life.
BTW, another source for free ebooks are public libraries. I download free ones from the Fairfax, VA library and they are good for 21 days. Check out the list of libraries who lend out eBooks here
https://wiki.mobileread.com/wiki/EBook_Lending_Libraries