Right -- I think I said that -- but those books are still the best place to start; pursue their recommendations individually to get updated prices, etc. (And the new Moon will be out this Fall.) In addition to the hostel sites dsc recommended, just google the cities/towns where you want to stay, and you'll find more options. E.g.,
http://www.bocas.com/ is a portal for Bocas; there are others. The three places Laura suggested are nice, but they're definitely not in the "student budget" category.