I urge you not to use this instructable to break copyright laws just so you can save hundreds of dollars on expensive textbooks, it would be a shame if the publishers didn't get any money from penny-pinching students. Keep this disclaimer in mind, I bear no responsibly for anyone's actions.
A digital book in PDF format
Enough paper to print the book
A place to cut the book
Step 1: Printing
Step 2: Cutting
Tips on cutting
Put a few sheets on top, that way you don't rip it
Avoid ripping as much as possible
Use clamps at the four corners
Step 3: Binding
Them carefully align the two sides it is even.
With glue, put it all over the spine, wait for it to dry
After the glue dries, put a couple sheets as a binding, with glue. Just get a blank piece of paper and glue it onto the front, back and the spine. It won't be big enough to cover it all, so you may want to reprint the front and the back, if needed.
Wait for the glue to dry, and you should be good.
I hope this helps, I'm doing this in college.