I had one college course with a custom edition and we still had the option of using the regular edition, (all the page numbers were the same the custom editions only difference was a lack of extra chapters that we weren't going to cover).
The custom edition was cheaper than the regular edition and this is the only reason the professor did this. The book didn't seem to have very many used copies being sold as it was an advanced class and people were more likely to keep the book than sell it.
Just providing context to how a custom edition can be cheaper if the professor does work.
I've also had many professors write their own book and give it for free in pdf or let you buy it for $20 at the university copy center already bound with the option of buying supplemental books that they thought were of good quality.
Maybe my engineering department was different but it seemed most of my professors tried to work to help the students not have to pay large amounts.
The custom edition was cheaper than the regular edition and this is the only reason the professor did this. The book didn't seem to have very many used copies being sold as it was an advanced class and people were more likely to keep the book than sell it.
Just providing context to how a custom edition can be cheaper if the professor does work.
I've also had many professors write their own book and give it for free in pdf or let you buy it for $20 at the university copy center already bound with the option of buying supplemental books that they thought were of good quality.
Maybe my engineering department was different but it seemed most of my professors tried to work to help the students not have to pay large amounts.