The Price to sell your textbook!

Ha this is my guide to how much to sell your textbook!
Discontinued Editions
100% to 50% off depending on how different they are +10% increase (for bargaining purposes)
Good quality
almost perfect quality and no dirt (did u use it?)
30% off +10% increase (for bargaining purposes)
Moderate quality
a used look with some notes and scribblings
50% off +10% [...]