Currency names for this world are Gold piece, Silver piece, and Copper piece, in the usual ten-to-one steps: 10 copper = 1 silver, 10 silver = 1 gold. Gold is serious money. Copper and silver buy meals, beds, and crossings. Do not make a bowl of noodles cost a gold piece.
STREET PRICES (starting points, adjust with scarcity and friendship)
Fire flakes at Red Tongue Flakes (Nara Jin): 2 copper a cone, 8 copper a bag, dragon-hot a silver.
Late noodles at Hwan's Night Noodles (Uncle Hwan): 4 to 7 copper a bowl. His favorite pot has gone missing — a street quest.
A floor mat at The Ash Lantern (Madam Sora): 4 copper. A room: a silver. She will hide a witness if she trusts you.
Public ferry hops (Batsu in the Caldera, Wudao in Yu Dao, Taktuq in Agna Qel'a): about 2 copper for a short hop, more for a crossing, much more for a quiet night run.
Wen's Broth: 3 copper a bowl, 5 with dumpling.
Two-Bowl Noodles (Mei-Lin): modest copper prices; she will talk if you help find a missing supplier.
Cabbages (Old Gan): copper by the head; wreck his cart and he will not forget, and he is not the later-war cameo merchant.
The Frozen Lantern (Iqaluk) and The Bison Bell (Mother Tashi): lodgings in silver or high copper, cheaper for pilgrims who help in the kitchen.
Warm Prune Pot (Auntie Niri): soup in copper; the lid-note is not for sale.
Orange Basket (Paljor): fruit and incense, copper to silver; bulk mourning incense is a clue, not a discount.
Saffron Wei's market mat: spice in silver; she needs an escort more than a haggle.
Qui's Jade: silver and gold, some of it with a dirty warehouse history.
Heng's Chute-Iron and Togaru's Warm Hammer: honest repairs in silver; Togaru refused a quiet chop and is having his coal stolen.
The Red Anvil (Old Pitou): blades and "special orders"; unusual spearheads are a plot, not just inventory.
Northfat and Bone (Pakak): oils, bone, and talk about stamps.
Maps and Beetle-Glass (Krik): maps at a steep silver or a favor; a library approach costs more than coin.
WHAT GOLD BUYS
A serious weapon, a month of discreet lodging, a bribe at a ring-gate, a forged set of papers, a long-distance berth, a foundry ingot sample, or a noble's attention. Lambak spirit-metal is priced in gold and in trouble. A Yuyan longbow or a masterwork Kyoshi fan is a treasure, not a market-stall impulse. Healing water from the oasis antechamber is a gift from Yupik, not a product; bottling the oasis itself is sacrilege.
VENDORS AS THE LIVING WORLD
A vendor who likes you will talk. Use them to advance the clock, move rumors, and place hooks. Recover Hwan's pot. Track Togaru's coal. Play tiles with Ko. Fix Gan's cart. Walk Mei-Lin's supplier road. Carry Niri's lid-note. Keep Fen busy at The Bison Bell so Paljor can speak. This is how a party learns the truth without storming a throne.
TRAVEL COSTS AND TIME
Island hops and canal ferries are hours to a day. Capital to Crescent Island or Ember Island is a short sea trip. Caldera to Yu Dao is a serious voyage. Ba Sing Se to Omashu is a long overland or bison flight. Poles to mid-latitudes are expedition travel. Air bison make the world smaller for temple friends and rarer for everyone else. Official barges already turn back civilian boats that "ask too many questions" about the eruption. That delay is a hook and a price.