Gold

Gold is the in-game currency of League of Legends. It is used to buy items that give bonus stats and abilities to your champion. There are some differences in gaining gold between the Classic and Dominion game modes.

At the beginning of the game, champions are given starting gold based on the game map played and can receive more gold through various means. Actively, champions aquire gold through last hitting minions, killing Epic Monsters, destroying enemy turrets, and killing champions (or assisting). Champions also passively generate gold which can be increased by gold generating runes, masteries, and/or items. The passive gold gain does not activate until minions spawn (at 1:30 on Summoner's Rift).

In Dominion, minions grant more gold than in classic, but champion kills and assists grant less. There is no global gold to be gained, but gold can be earned by taking capture points.

Starting Gold
Your champion starts with 475 gold in Summoner's Rift, 825 gold in Twisted Treeline, and 1350 gold in Dominion. This starting amount can be increased by:
 * +25/50 with the  mastery
 * +25 with the mastery (Maps other than Summoner's Rift)

Passive gold gain
The gold a champion earns without actively killing units is called passive gold gain. Every champion passively generates gold at a rate of 16 every 10 seconds on Classic, and 56 every 10 seconds on Dominion. This gold gain does not begin until minions spawn at each base (from 1:30 onwards). Passive gold gain can also be the result of runes, summoner masteries, or gold generating items.

Items

 * grants an additional 2 gold every 10 seconds and 2 additional gold per enemy unit killed.
 * and  both grant an additional 4 gold every 10 seconds but do not stack with one another.
 * grants an additional 5 gold every 10 seconds.

Masteries and Runes

 * The mastery grants an additional  gold every 10 seconds.
 * Greater Quintessences of Avarice grant an additional 1 gold every 10 seconds
 * Greater Seals of Avarice grant an additional 0.25 gold every 10 seconds.

Killing Pets, Minions and Monsters
Gold can be earned by landing the killing blow (last hit) on enemy team minions and neutral monsters.
 * The gold earned from minion kills is dependent on the game time. As the game progresses, each minion is worth more. On Twisted Treeline melee and caster minions gold rewards increase by 1 gold after the 1st wave and 1 gold per 5 minutes after that. Siege minions gold rewards increase by 1 gold every 2-3 minutes.
 * The gold earned from neutral monsters also increases over time depending on when the monsters were spawned. In addition the largest monster in a minor camp will slowly increase gold value to a modest cap after approximately two minutes.
 * Pets such as or  will grant gold to the champion that killed the pet.
 * will grant 10 gold to the champion that kills it.
 * Certain kinds of monsters called epic monsters give gold globally, providing gold for the entire team regardless of which individual champion landed the killing blow, although the champion that does so will receive an additional 25 gold.

Champion Kills and Assists
Gold can be earned by killing enemy champions. The gold gain associated with a champion kill is determined by how many kills the slain champion has recently accumulated (champions that have killed many enemies without dying are worth more gold). When a champion is killed, the bounty ranges from 15 to 500 gold.
 * The last hitter always receives 100% of the value of the bounty.
 * An extra 50% of the value of the bounty is put into a gold pool. The pool is split equally among all champions who assist (by damaging or debuffing the slain champion or healing/buffing the champion that made the kill within 10 seconds of the kill). If there are no assists, the pool is lost.
 * An extra 100 gold is earned for getting First Blood.
 * In Season 2, was a defensive mastery that will increase the gold earned from all kills and assists by 8/16/24 gold for the affected champion; this effect is halved on the Crystal Scar.

Destroying a Turret
Whenever an enemy turret is destroyed, every member of your team receives 150 gold, regardless of their position or state.

Destroying the Inhibitors/Nexus
Destroying an inhibitor or the nexus will grant the player 50 gold, but the latter is irrelevant, as it also causes the game to end.

Destroying a Ward

 * Destroying a or a  will grant the player 25 gold, this includes the ward from.
 * Destroying a  from a or  will grant the player 10 gold.

Champion Abilities
Some champions have abilities that grant them additional gold under certain circumstances.
 * passively grants her bonus gold for every enemy unit killed.
 * grants a bonus gold if it lands the killing blow to an enemy unit.
 * grants him and his allies 2 bonus gold per kill.
 * grants 10 gold when used when enhanced by the mastery.

Items

 * grants 2 additional gold per enemy unit killed in addition to its 2 gold per 10 seconds passive gold gain.

Masteries
Some masteries provide an active means to acquire gold.
 * mastery grants +3/5 gold for attacking a enemy champion with range/melee basic attack.

Seizing Capture Points In Dominion
Players gain 100 gold for neutralizing a point, and 100 gold for capturing a point, except for the first time capturing any given point, wherein every point captured is worth 100 gold. This number is dependent on the number of champions involved in the capture of a point. 2 champions will each gain 75 gold, 3 champions will each gain 63 gold, ect.

Selling Items
Items can be sold back at the shop for 70% of their total cost. Items that generate gold and Prospector's items only return 50% of their original cost; Doran's items only return 40% of their original cost.

Max Gold per 10
By buying all the gold income items, and using the right masteries and runes, the player can achieve a total of 34.25 gold per 10 seconds on classic and 74.25 per 10 on dominion. Calculated as follows:
 * (9 Seals + 3 Quints + 4 Masteries + Avarice + Philosopher's + Kage's + Map)
 * (9 * 0.25) + (3 * 1.0) + (4 * 0.5) + 2 + 5 + 4 + 16 =
 * (9 * 0.25) + (3 * 1.0) + (4 * 0.5) + 2 + 5 + 4 + 56 =

Individual Stat Costs
Cost chart: