Bazaars are npcs in trade cities (not to be confused with trade outposts) that allow for the buying and selling of items. Players put up their items for sale and other players can buy them. Items vary between cities.
Right-Click or do '/bazaar browse' to browse the stock. Each item being sold is a different price, so do your research before buying! If you want to be the seller, do '/bazaar deposit (item-id)'.
A portion of the profit goes to the settlement. Tax rates can range from Zero to Twelve percent.
Doing '/bazaar browse' works in any location, but costs twice as much when not in the trade city.