From free two-day shipping to free movies and music, Amazon Prime offers subscribers quite a lot for its $99.99/year fee. It offers so much, in fact, that Amazon should be losing money for every Prime subscriber it has, so why does the company keep pushing the service so aggressively? Unfortunately, that’s closely guarded secret at Amazon but many expect that it’s because Prime users spend much more on average than regular users, enough to cover the cost that Amazon pays for Prime and then some.