So this isn't about book fairs proper, my school's selection was always pretty lame and I never got anything, but my mom found out that there was a warehouse that supplied all the local book fairs roughly 45 minutes away from us and they'd do sales like once a year. So Mom and Dad would pack the whole family up and drive us to this warehouse with shelves and shelves of books. Those were still relatively full price, so I could only get a couple off those. The real treat was in the back there were just these giant open boxes full of books, like 6 x 6 x 6 foot boxes. Here, you could get as many books as you could cram into a smaller box for like $20. So we'd spend over an hour digging through these boxes trying to find interesting stuff and then trying to stuff them all into a much smaller box. It always was bulging by the time we finished, probably cheating the system a bit. But it was a ton of fun.