We’d get a second-hand book sale just before school starts where there school would on-sell used books bought back (or donated) from previous years. All the parents and many kids would look for the book in the best condition. If you knew what was up, you’d thumb through them all and look for the ones with highlighting and the margin notes. My parents were like “why do you want the ratty old one?” But didn’t press the issue too hard cos at least they were cheaper than the pristine ones where the spine had never been cracked.