there are many ebook sites which provide free ebooks....but some are difficult to get....
sometimes, when searching ebook, free download link come first after buying site(official)..... i think, publishers may give support for marketing their books by providing free ebook copy....also original ebook comes in different format....
once i only bought from ebookmall which is pdf with drm protection, but managed to remove drm

but these days, ebooks comes in different format....
Code:
http://www.24x7books.com/books24x7.asp
http://my.safaribooksonline.com/alltitles
http://www.coursesmart.com/disciplines?category
http://www.knovel.com/web/portal/browse
http://www.crcnetbase.com/products.asp
http://www.eblib.com/
http://myilibrary.com/
http://www.dawsonera.com/
http://shop.ebrary.com/
http://www.sciencedirect.com/
http://www3.interscience.wiley.com
http://www.informaworld.com/smpp/home~db=all
http://www.springerlink.com/home/main.mpx
http://www.rsc.org/Publishing/index.asp
http://ebooks.whsmith.co.uk
http://www.ebookmall.com
http://www.ebookstore.tandf.co.uk/html/index.asp
http://www.netlibrary.com/
https://ebooks.primisonline.com/eBookstore/
http://gateway.ovid.com
http://www.gale.cengage.com/
http://www.igpublish.com/
http://ebooks.worldscinet.com/
Has anybody bought ebook? pls share ur reviews.