When class is over, most students set their old books aside and move on to the next ones. Some might sell their books back to the campus bookstore or privately to other students. This is definitely a better option because it gives you something instead of nothing. Of course, if you want to get even more out of your old books, you should look at the possibility to sell textbooks online. The internet gives you a bigger audience to sell to and a chance to make bigger profits when you are selling your old books, no matter what they might be.
If you want to sell textbooks, you have to take the time to find the best resources to do so. That includes making sure that you find websites where you will be able to get the most for your books. Not all of the websites that you find are going to be the best, so you will need to make sure that you explore the options and figure out what is going to get you the most out of your used textbooks. It might take a little bit of effort, but it's easy to earn money from your old books online.
You have to be a bit realistic when you sell textbooks online. You can get a lot more than you would get from the local bookstore and having a larger audience means that you can probably get more than if you sold them to other students at your school, as well. However, you're not going to make your money back, by any means. Most books sell for about 50-80% of their value, and the ones that are worth more are barely used. Plus, you have to calculate in the cost of shipping. If someone can buy a book for the same price at their local campus bookstore and not have it shipped, they're going to choose that route.
The bottom line is that you can sell textbooks online as a way to get more out of your investment. However, you shouldn't expect to charge top dollar because that's just not realistic. Take the time to find the best resources that are available and sell your books wherever it's convenient for you. Make sure that you get everything that you can out of your online experience because your old books can become your new spending money, or even cash for next semester's textbooks.