Big corporations (such as your national postal service) often print out brochures and magazines with useful information, which are distributed for free.
Meanwhile, scammers post ads online and in newspapers making it look as if the ad comes from the corporation. The ads claim the company is hiring and those interested are required to call a number.
Once the victims call, they are asked to purchase the company’s study guide first, to give the applicant an insight into the company. They only charge a few bucks for this, so the job seeker pays up and in the post receives one of those free brochures, which the scammer has harvested from several places.
How to avoid: always check if the real company is hiring by calling the HR department or looking at their “Careers” section online.