Buyer Beware don't get ripped off.
This is something I have noticed for some time on Ebay.
Some ebooks are original content, some ebooks are copies of books that are out of copyright, some are just a rip off.
So how can you get value from an ebook download.
If the information is original content, then there is usually an authors website to back it up e.g.
Sometimes you will see an out of print, out of copyright book being offered as an ebook.
Please check out :- www.archive.org before you purchase information that is already freely available.
Basically check before you buy an ebook.