That's actually a pretty good idea. The difference between the newest edition and second newest edition of a book can be up to $100 sometimes. For example the my intro circuits book cost me $100 used (http://www.amazon.com/Electric-Circuits-8th-James-Nilsson/dp...) for the newest edition when I could have gotten the second newest one for $5 (http://www.amazon.com/Electric-Circuits-7th-James-Nilsson/dp...)