Minions spawn infinitely towards the enemy nexus. Two waves have three ranged and three melee minions. The third wave has the 3 and 3 but also a canon minion which has more health, does more damage, and is worth more money. Regarding money: if you kill or assist in killing an enemy champion you get money. If you kill a jungle monster, you get money. Two of the camps have a large monster that gives you a buff. If you do lethal damage to a minion (last hit) you get money. If you damage an outer turret's armored plates, destroy the tower, or the inhibitor, you get money. In addition to towers, other objectives (things to kill/destroy) include dragon, which is just that and it gives a soul which increases damage, or health regen, or movement speed, or ultimate ability cool down reduction. Rift herald is a large shelled creature that when you kill, you can summon for the fast destruction of towers in any of the three lanes. Since money makes you more powerful when you buy the right items, if you have more than the enemy you face off againat you will be able to do everything faster and generate even more money which makes a feedback loop called a snowball.