Everything you wanted to know about abstract algebra, but were afraid to buy
This text is free to download, but if you are doing more than just browsing, then purchasing a print copy is less expensive than printing it on a laser printer, less expensive than a single copy (unbound) at a copy shop, and very close to prices charged by copy shops when ordering multiple copies at a discount. Before ordering, you might want to examine an evaluation copy.
A nicely printed and bound (hardback) copy of the 2011-12 edition of AATA can be purchased from Amazon.com for $19.95 via the link below. This is a service provided by Lon Mitchell. The author, while supportive of this edition, is not involved directly in any way, including financially.
A note about editions: There have been some discrepancies in chapter numbering across editions. Both the print-on-demand versions start with Chapter 1, but the 2011 Edition contains a split of the chapter on normal subgroups and homomorphisms, so later chapters have new numbers. The original text, and some subsequent PDF versions, started with Chapter 0. The print-on-demand 2009 version lacks some highlighted inline definitions.