What's that

ok say your playing a game and lets say there are 2 forms of money in destiny, (lets just say Cash- and....Space magic crystals) you buy everything like ammo, guns, armor, ect.... with cash. but you can trade in the crystals to get lets say loot chest of different rarity, (say 10 crystals for common, 30 for rare, and 100 for legendary) ok then imagine that you are lazy, you can just spend real world money for in game purchases, soooo 2$ dollars for the common loot chest, $5 for the rare, and $10 for the legendary, thats a micro-transaction. and they run RAMPET IN ALL MMOs.