The funny thing is that if you look at the cost of the USED books, (as opposed to buying new) the hardcovers are often CHEAPER than the mass market versions.
Which drives me nuts because I like the MMPB versions best, and I can't really afford to get books new at all so it's frustrating. I love our library book sale, and one of the used book stores in town has a 25-cent shelf (remember I live in the US right now; not sure what that would be the equivalent of for everyone else here, but that's REALLY CHEAP), but otherwise buying books is a process I agonize over, because funds are always hard to find