League of legends is a FREE game. Players in the game can get Influence Points by playing games. Influence Points is a type of currency, you can buy campions and runes with Influence Pionts. Players can also get riot points by buy them with real money. With riot points you can buy Champions, skins, hextech crates, and gold and exp boosters. When buying Riot points the price are from $10, $25, $50, and $100. $10 worth of RP can get you 1380RP. $25 worth of RP can get you 3500RP. $50 worth of RP can get you 7200RP. $100 worth of RP can get you 15000RP. RP card are available at places like Best Buy, Walmart, Gamesto and 7/11.
Their are many categories of skins in league of legends. One of the categories of skins are called clasic skins, clasic skins are the cheapest skins (390RP/560RP) in the league market becuase only little is changed to the look of the champion. Another category is royal skin(750RP) these skins contain more changes then the clasic skins. Epic skins that is another category (975RP), these skins are changed a little more then the royal skin. Imperial Skins (1350 RP) in league have some of the coolest skins in the game but no the best. Legendary Skins (1820 RP) are the best skins for most of the league champions and they have alot of work put into it. Ultimate Skins (3250 RP) are the best skins in league, they have awesome animations and even music. Fun fact their are only 4 Ultimate skin in league of legends so far.