I have been monitoring the price of a couple of textbooks on amazon. over the past few weeks, prices have gone through the roof. a book that used to cost $20 now costs $70. a book that used to cost $85 now costs $180. I guess that's because of back to school. but doesn't school start end of august, beginning of september? I have these 2 books that I mentioned above. should I sell now or wait til end of august when everybody is going back to school?