Kenshi trading: finding items and reading prices
Buying starts with a shop whose stock list carries the item, and ends with a price the game builds rather than the value in the item's record. A 
Spiked Club is stocked under weapons in a long run of towns, Mud Town among them. Its shelf price comes from its record value, its maker and its quality, and a trader buys it back for a fraction of that.
Where an item is stocked
- Value in its record
- 160
- Stock category
- Weapons
- Towns
- Bad Teeth, Black Desert City, Drin, Holy Military Base, Manhunter Base, Mud Town, Narko's Trap, Okran's Fist, Okran's Shield, Rot, Scraphouse, Shark, Stack, Stone Rat Village, Trader's Edge, Watchtower
- Sold by factions
- The Holy Nation, Mercenary Guild, Swampers, Skeletons, Blackshifters, Stone Rats, Twinblades, Grayflayers, Hounds, Anti-Slavers
A stock list is a possibility, not an inventory. A town that lists clubs can have none on the counter on the day you arrive, and a shop that has one sells the quality it happens to hold. The supplier lookup opens with the club selected and lists every town, shop and faction whose stock carries it. Each town opens its own page and its place on the map.
How the game prices a weapon
The value in a weapon's record is only the first input. The game multiplies it by the maker's price modifier, scales it by the weapon's quality and applies the weapon price multiplier, 0.40. Recomputed from the records, this is the tooltip the game itself showed for an 
Iron Club:
Iron Club- Value in its record
- 80
- Maker's price modifier
- 0.30
- Quality level
- 10
- Weapon price multiplier
- 0.40
- Trader's buying multiplier
- 0.25
- Value the game shows
- 198
- Sell value the game shows
- 49
Armour that covers body parts ignores its record value: its price comes from its class and material. Clothing takes 1.00, food crops 0.50, and other goods the trade price multiplier, 0.60.
What a trader pays you
Selling takes a cut of its own. For weapons and armour a trader pays 0.25 of the value, the Sell value line on the same tooltip. Other items sell at 0.50 of their value.
Why prices differ between towns
Each town draws its own price factor for every trade good, at most 0.30 above or below one, and towns that lie close together hold similar factors. The trade window then applies one more factor that depends on who you trade with, so the final figure is the one the trade window shows.