I got roped into an audible plus membership while searching for a few audiobooks. It said that I could listen with audible plus but that was extremely misleading. It is incredibly difficult to find books that are part of plus. You have to browse the plus site under Discover. There's no search feature that lets you find exactly what you are looking for. They also have a very confusing tiered subscription system. Scribd still seems to be the best alternative but doesn't have a huge catalogue.