The writing industry is filled with entrepreneurs who exploit new authors. Even the more legimate businesses often have their dark side. Writer's Digest, for example, carries advertising for vanity presses and questionable literary agents.
Many new writers fall for suspect schemes and outright scams.
Mostly because they don't understand how the publishing industry works, and they let vanity get in the way of common sense. Many reputable literary agents charge nominal handling fees for manuscript submissions. Because the vast majority of submissions by new writers are unlikely to be publishable, agents can justify passing their clerical and postage expenses along to aspiring authors. In such cases, it becomes fairly obvious that the agents are making bigger profits from reading than from selling. First, by avoiding agents who advertise.