ECONOMY
Marketplace
The marketplace is an automated market maker. You trade against a pool rather than another player's order, so a trade always fills, and the price moves with the size of the trade you make.
Access
Pools are gated by rarity against your marketplace level. Common goods trade from level one; the rarest need the top level.
Daily limits
Free accounts have a daily volume cap that rises with marketplace level. Premium removes it.
Fees
Most pools charge a fee that scales with your level, and part of it goes to whichever alliance holds the Market Square district. The currency pool is the exception: see ASH and $ato.