In cities in IR, the auction house was the contrary existing figure to trade houses that existed in towns but with more features and was also more profitable for players.
Trade houses were buildings that sold items at a cheaper price than the market rate. While this was advantageous to buyers, it wasn't the same for sellers. The only advantage it had towards those who sold their products was that it allowed them to quickly convert the item or equipment into money.
When a player was to sell a certain good at the trade house, it would be done so at price cheaper than the market rate and sold at a price slightly above that but still
Cheaper than market rate to others. In other words, those who sold their products or items in trade houses, actually took a loss when comparing the price to other places whereas those who bought from trade houses profited the most.