Like the commercial market, open access has its share of scrupulous publishers. These predatory journals and publishers often require huge fees from authors before publishing their work. Jeffrey Beall, a librarian at the University of Colorado at Denver, has worked extensively to identify these predators. His list, which is linked below, is constantly updated but is not complete by any means as predatory journals spring up overnight. The number of predatory open access journals, though, has been estimated to be around 25%, so don't let these publishers cloud your overall judgment about open access.