Finding used books online isn't exactly a chore. From Amazon to ebay to points beyond, there are a myriad, or even a plethora, if you will, of websites that sell used books online. You can buy in bulk for the best prices, or pick and choose as your needs dictate. Either way, with a little bit of time and willingness to search, you'll most likely be able to find whatever book it is you need online.
Of course, there's an alternative to buying used books online. It's called the Library. You might have heard of it. Or heck, you might even remember it from your days as an impressionable youth, studying your way through grammar school and points beyond.
The library is pretty much the ultimate book store. Here in New York City, the entire city's library network is linked, meaning you can go into your local branch and search for whatever book you want. If you're not able to find it, they can then place and order for it from one of the main branches, and it'll arrive early the next morning. It's a 24 hour wait, but that's still less than the amount of time you'd have to wait for most used books online... and, of course, it's free.
Yay library!
The main library in New York City is on 42nd Street and Fifth Avenue at the heart of midtown Manhattan. It's part of "Bryant Park", and it also doubles as one of the secretly greatest museums in what is (in my humble opinion, of course) the greatest city in the world. From original transcripts of momentous presidential speeches to original pressruns of magazines like The Atlantic and The New Yorker, the Bryant Park library is a little slice of heaven for someone who's interest in not just American history, but American literary history. It's head-and-shoulders above any other site in the states when it comes to that particular academic niche.
And it's free. That's the thing about folks who run out and purchase books, both old and new - I think they forget that they don't need to buy when they can just check out a copy and not spend a penny. How many books do you really need to own and keep around the house, anyway? I have maybe a half-dozen that I'll read over and over again - Catch-22, The Source, Siddhartha and a few others - but beyond that, there's no reason not to just check whatever I happen to be reading out from the local branch, then bring it back when I'm done.
So save some trees and use the library. In these tough economic and environmental times, every penny and every tree counts!