You can get a 505 on the "flea market" forum here at mobileread. The 505 is no longer being manufactured. The PRS-600 took its place.
The PRS-300/600, Pocketbook 360..... there are several good options.
Actually go to this link
http://www.frys.com/product/5432609 you will see they are out of stock. But, check for local availability... I checked where I am and they have new 505's in stock in Arlington Texas.......