CryptoKitties is blockchain game. In this game you can own, trade and breed kitties, and that is all and reason why game have this name. U have three ways to trade or transfer kitties: using sales auction, using core contract, using offers contract. If you trade kitties with sales auction, the game publisher chages sellers for 3.75% of deal price as a handling fee. Same rate will be charged for offers contract. When calling any function in each contract, the players also need to pay gas fees to Ethereum miners through their Ethereum wallet. The gas fee is usually between 0.0001 ethherium and 0.01 etherium. You have two ways to breed a new kitty;