Welcome to MR, Ian.
I have had my Sony 505 for a year and a half and love it. I do use the Sony Library (mostly for the free books and to drop my books into collections). You can get a cheap wall (mains) charger and it will charge much faster. The Sony PSP charger will work and is much cheaper than the "official" Reader charger.
Have you checked the MR Wiki
page dedicated to free ebook sites?
Also, MR has free ebooks that have been beautifully formatted by some very dedicated MR members.
ePub format and
Sony BBeB / lrf format
You can check these ebook sites..
feedbooks.com and
manybooks.net and
Project Gutenberg
Plus these free and for purchase sites ..
smashwords.com and
baen.com Plus Baen has a
free library
You can explore using
Calibre to manage your library of DRM free books and Kovid, the creator, frequents the forums here. We even have a dedicated
Calibre forum.
Finally, you can use these book search engines for finding and comparing book prices..
AddAll,
eBookPrice.Info, and
Inkmesh.
I hope these links have been helpful.
Have fun in the forums and ask if you have any questions.