GOLD (abbreviated in-game as G) is the main currency used in the Underground.
The protagonist gains GOLD primarily through winning encounters, whether that be through killing the monsters or sparing them. Fleeing a fight is not considered winning and, thus, does not award any money, although money can still be won if another monster was spared or killed in the same encounter. Killing monsters usually awards more GOLD than sparing them (with some very few exceptions). Depending on the monsters fought and the actions performed in an encounter, winning an encounter can award anything from nothing to more than a hundred GOLD.
Sources
Other than through participation in an encounter, GOLD may be accrued through the following means:
- Selling items in the Tem Shop.
- The fastest method, which requires the protagonist to have the upgraded Cell Phone obtained after meeting Alphys in the Lab and have a minimum of around 300G, the protagonist can purchase a full inventory of Cloudy Glasses from Gerson at 30G each and then sell them to the Temmie Shopkeeper at 50G each. The profit can be used to buy more Cloudy Glasses per trip. It costs 840G to fill up all 28 slots of both boxes and the protagonist's inventory with Cloudy Glasses. Selling all 28 glasses gives the protagonist 1400G at a 560G profit per trip.
- If the Temmie Shopkeeper talks about wanting the Cloudy Glasses, but needing to pay for education, she offers 51G instead of the usual 50G. It is best to refuse at first, as the Shopkeeper then offers 65G, at which point the offer should be accepted as it does not go any higher. This usually happens every 8 sells.
- The protagonist can also decide to obtain the Dog Residue from the Piano Puzzle, place their entire inventory into a box, use the Dog Residue, and then sell all but one Dog Residue to the Temmie Shopkeeper for 1G to 4G each. Dog Salads may also spawn when activating the Dog Residue, and sell at 8G each.
- The protagonist can also buy Temmie Flakes (on sale) for 1G, and sell them for 2G, but this method requires much more time than other ones.
- The fastest method, which requires the protagonist to have the upgraded Cell Phone obtained after meeting Alphys in the Lab and have a minimum of around 300G, the protagonist can purchase a full inventory of Cloudy Glasses from Gerson at 30G each and then sell them to the Temmie Shopkeeper at 50G each. The profit can be used to buy more Cloudy Glasses per trip. It costs 840G to fill up all 28 slots of both boxes and the protagonist's inventory with Cloudy Glasses. Selling all 28 glasses gives the protagonist 1400G at a 560G profit per trip.
- Standing on the pink monster's face in Waterfall, and letting them ferry the protagonist back to the entrance. (Gain 3G per trip)
- Finding loose GOLD in a snow poff, in the couch in Papyrus and Sans's House, and in one of the trash cans in the CORE.
- Receiving tips from the MTT Resort's guests while acting as room service.
- Placing in a certain rank in a Thundersnail race.
- Coming in 1st place. (9G prize, a net loss of 1G)
- Barely coming in 2nd place. (30G prize, a net gain of 20G)
- Interacting with the flag after playing the Ball Game found in Snowdin Forest rewards the protagonist from 1G to 5G, depending on which flag they got. Getting the red flag rewards the protagonist with 50G.
- In the Genocide Route, the Snowdin Shopkeeper is absent and 758G can be stolen from the till. Bratty and Catty are also absent, which allows for 5G to be stolen from their till.
Transactions
GOLD may be exchanged for these various goods, services, and effects:
- Items sold by vendors (funding the Temmie Shopkeeper's college education is listed as an item).
- Thundersnail games (10G per game).
- A stay at the Snowed Inn (80G per overnight stay - this is refunded as the protagonist does not stay overnight).
- A stay at the MTT Resort (200G per stay - no room key provided).
- Muffet (spending increasing amounts of GOLD is an ACT option during the battle with her that lowers her attack for the turn).
- A gift for Gyftrot.
Trivia
- In the Undertale Demo, the currency used was "GILD", a verb meaning "to coat with gold." It may also have been a reference to Gil, the staple currency of the Final Fantasy series.
- Upon interacting with the couch in Papyrus and Sans's house, the narration states that the protagonist has found a bunch of loose coins. This suggests that GOLD's physical form may be coins or gold coins.