They say if you love something, give it away. Well, if you wanna make bank on a video game, the same rule applies.You might never pay a dime to play League of Legends but by utilizing the microtransaction revenue model, LoL earned $624 million in revenue in 2013. The average player was dropping about $40 on the game, mostly for just aesthetic enhancements like new character skins. In spite of its huge popularity, LoL wasn’t even the world’s top free-to-play game, according to Super Data Research’s annual report on the US digital games market. The top free-to-play game was the first-person shooter, Crossfire, which is relatively unknown in America but earned $957 million last year, on the wings of its popularity in Korea, China, and the Philippines.The in-game microtransaction is an occasionally divisive revenue model—one of the critiques of Crossfire is that you can essentially just pay your way to better weapons and armor, which gamers hate—but there’s no denying that it’s a successful one as well. Microtransactions are popping up all over the gaming landscape, even beyond the confines of “free-to-play.”Superdata’s report also noted that mobile gaming grew by 29 percent to $3.1 billion industry last year, and many of those games, such as Candy Crush, also rely on a micropayment system. This “free sample to get you hooked,” model can occasionally backfire on companies, as Apple found out, when the FTC ruled that the company had to pay back at least $32.5 million to account holders whose children had made hundreds of in-game purchases without their parents’ knowledge, but that’s a snag that will be worked out by the App Store. It’s safe to say that people in the industry noticed that Candy Crush was earning $3.5 million a day last year.Even the traditional gaming paradigm, console gaming, is getting into microtransactions. The upcoming version of the popular racing franchise, Gran Turismo, will be the first to offer players the option of purchasing in-game credits that can be used to purchase cars or other items, rather than having to race to earn those credits. If you just want to drive one of the game’s most expensive cars, the Jaguar XJ1, you have the option of spending hours racing for 20 million credits, or you can drop $130 on it and away you go. Grand Theft Auto V added microtransactions to its online mode, which has, appropriately enough, lead to players cheating to earn more credits to buy things like boats and better cars and guns.Free-to-play massively multiplayer online games were ascendant last year with their revenue rising 45 percent to $2.8 billion, while pay-to-play MMOs dropped by 19 percent. Players are leaving World of Warcraft, and Nintendo announced its third straight annual loss Friday. The paradigm is shifting in video games, and it might not cost you anything to see where it’s going, but it might cost you to stay.