In-game fees have grown prevalent in free games. This is plainly obvious when the game deliberately withholds information or annoys you in order to force you to spend money on "power-ups."

The catch, it seems, with playing free games is that they will use any means necessary to get you to pay, often for much more than the game would cost if purchased directly. This strategy works, and some people end up spending a lot of money on video games without ever realizing it.