$15 just to remove ads. $60 for extra speed, which still feels quite slow. You can also spend another $44 to double up that speed with all three packs. You have mines, then crafting. Then a small skill tree, which half of it takes premium currency. You also can get mine boosts which cost premium currency. These mines will go slow otherwise. I've seen casinos in Las Vegas that give more than this does for cheaper, and with more depth.