Some spell books (bliz for example) are becoming more and more common. How about using a 2nd or 3rd+ book to give 10-20% of points needed to level the spell? Maybe make it so it only works on uncommon and above books, to stop people just leveling spells from shop.
It would keep books rarer for 1st time buyers, because there will be less on the market and help spell books keep some value once most people have the book.
It would keep books rarer for 1st time buyers, because there will be less on the market and help spell books keep some value once most people have the book.