But first, let me explain what a custom textbook is just in case all of your professors are smart enough to not make them and you've never experienced one. Basically, they work with a publisher of a textbook and usually just take out a few chapters that this particular professor isn't going to use, and then sell the book to the bookstore for less money than the full retail price of the book because there is less content they are paying for I guess. Professors get all excited because they get to save students money and they think they're so cool. But allow me to tell you why they're not cool.
1. They change the ISBN number. So, when you look up online what book you need for the class, and then you type the ISBN into Amazon looking for some used deal, nothing comes up. Because its custom. For your professor only. So it's like, rare.
2. This means that the only place to buy the book is at the bookstore, so you can rarely get a used one. And yes, it is cheaper than the full retail price of the original would be, but it's usually like $100 instead of $175 or something ridiculous like that. And there's probably $6 used copies of the full edition (WITH ALL THE CHAPTERS) on Amazon but you can't get them because you don't have the ISBN like you do with all your other books. YEAH THANKS FOR ALL YOUR MONEY SAVING HELP, PROF.
3. You have to by the book INSIDE OF THE BOOKSTORE DURING THE FIRST WEEK OF CLASS. You have to go all the way there, stand in 10 million lines, and pay 10 billion dollars for this stupid custom edition instead of sitting on your couch paying Amazon and having it delivered to your door.
4. Then on the first day of class we ALL get to sit and listen to the teacher give their spiel about how excited they are to be helping us out like this.
5. At the end of the year, you can't sell it back to anywhere (like Amazon) except the bookstore. Because it's a custom edition. And they usually give you like, 1/3 of what you payed for it. (See how I'm still not saving money on this?)
So I had to do all of this, as you may have guessed. Except step 5, of course. But after I bought the book, I took it home and not only did I find $6 used copies on Amazon after searching by author (because another thing about textbooks is that the edition doesn't matter so if you get the second most recent one you're really not missing anything), but I found a full 600 page PDF of the entire book FOR FREE on the interwebs. Thanks interwebs. I downloaded it into my iBooks and now I have it forever.
So then I got to stand in another line to return the book. But at least I got my $93 dollars back.