Actual way for earning xp AND Toy box money: 1.Make a slingshot. 2.Change the ammo to the one that looks like a black ball. 3.If you Completed Avengers, build the large frost giant. 4.Set difficulty to extreme. 5.Shoot them with the slingshot while the sparks go to you. 6.Enjoy! I will post a picture on how many sparks i am getting in a minute.