College tuition is expensive enough, but hitting the campus bookstore with a shopping list of textbooks is where you can really get gouged—unless you know where to find the best discounts. With the start of the school year right around the corner, we asked savvy student deal hunters the best way to save money on textbooks. Over 100 responses later, we've compiled the best sources and tips to that will get you the textbooks you need without breaking the bank. The majority of responses were specific web sites readers had used to save money on books. We've subdivided the textbook sites into categories for you, followed by tips and tricks for saving on your textbook haul this semester.

The Comparison Engines

When the price matters more than the store, online textbook price comparison engines shine. When you don't care what truck your $200 Chemistry book fell off of or what far reaches of the world it has to travel from to get to you as long as it's dirt cheap, comparison engines are the perfect tool. BigWords.com is by far the most popular comparison engine amongst readers. BigWords has expanded over the years to cover not just the buying and selling of textbooks but price comparisons for DVDs, music, games, and other consumer products. According to the self-published statistics on the site:

Multi-Item Price Optimization™ saves about $173 on average multi-item orders, including coupons, promotions, and shipping*. 35% cheaper than other online stores, 50% cheaper than bookstores.

Based on personal experience, while I have no idea if BigWords is in fact 35% cheaper than their competitors I have saved tons of money buying books with their comparison engine over the years. The real deal-sealer, of course, is the giant orange robot they employ as a mascot. You can always trust a robot. While AddALL's web site isn't as polished as BigWords', it does search 41 book sites, ensuring that whether your book is on Half.com or Walmart.com you'll end up with a low price. Unfortunately, AddALL cannot do multiple comparisons like BigWords can.

Rent Your Textbooks

Taking a hybrid approach between selling books and lending them, Chegg.com is a book rental service. From the test searches I conducted and from the comments left by readers it would appear that renting a book from Chegg for a semester is roughly 50% the cost of purchasing it. Chegg does offer the option to outright purchase the book if you so desire, but as any seasoned college student can tell you there are many books you'll never use again. If you're looking for an environmentally conscious bookseller, Chegg is an excellent candidate.

When we realized that 20 million trees a year are consumed for books—four million for textbooks alone—we decided it was time to give a little back to Mother Nature. That's why we plant a tree for every book you rent, buy, sell or donate! Together we can make a difference, one book at a time.

Booksellers and Marketplaces

A powerhouse in the regular book industry, it didn't take long for Amazon.com to branch into the realm of textbooks. While Amazon didn't always have the lowest prices in my informal testing, some readers pointed out that there is sometimes more to shopping than getting the absolute lowest price. Amazon has a history of strong customer service, and the few extra dollars you may spend buying a book through Amazon.com might be worth the saved headache if things aren't quite what you expected. Also, Amazon offers a 30-day price guarantee, so if a book's price drops after you buy it they'll refund you the difference. If you buy from Amazon, use a service like RefundPlease to monitor your purchases for price drops for 30 days after your purchase. Half.com has built a name as a place to quickly buy and sell used books—and textbooks are no exception. With a spartan but efficient interface you can quickly enter entire lists of books to buy or sell and find out the going rate. Keep in mind that most textbook comparison engines will check sites like Amazon Marketplace and Half.com, so visiting a single specialized retail site isn't always your best first stop.

The Free: The Library and Friends

The most obvious (and maybe most overlooked) place to find books is at the public library. Many college libraries maintain a reserve of popular textbooks. If your library doesn't have the book you are looking for, check into getting it from another library. If you're new to using the library, see how to get the most out of your local library. Finally, don't forget to simply ask around—online, like on Facebook, or in person. If you're a college student purchasing textbooks there is a pretty good chance you're in an area saturated with other college students who are all just as dismayed at the idea of selling back their $180 textbook to the campus bookstore for $15. Ask around, because no matter how cheap you find a book in a textbook search engine, nothing beats the hassle of giving a fellow student $20 and being done with your textbook hunting on the spot. Tell us about your best textbook discounts this academic year in the comments.

Send an email to Jason Fitzpatrick, the author of this post, at jason@lifehacker.com.