You will still buy a few books that they don't have available, or that you really want to consult every day for a year; but you can save a lot of money, time, and space by visiting your local library before you visit amazon.
Time? I get the idea with most of them but it takes me a couple of hours to get down to the library and back whereas it's like a couple of minutes to order from Amazon or somewhere.
Many library catalogues are searchable online. So you just have to search a different site to wether they have it or not. If they have it, it's probably quicker to take a trip to the library than to wait for shipping.
Thus spake Eliezer:
It seems that many here might have outlandish ideas for ways of improving our lives. For instance, a recent post advocated installing really bright lights as a way to boost alertness and productivity. We should not adopt such hacks into our dogma until we're pretty sure they work; however, one way of knowing whether a crazy idea works is to try implementing it, and you may have more ideas than you're planning to implement.
So: please post all such lifehack ideas! Even if you haven't tried them, even if they seem unlikely to work. Post them separately, unless some other way would be more appropriate. If you've tried some idea and it hasn't worked, it would be useful to post that too.