So far, from what I have seen, the only form of offline trade happens through the tribe totem pole. Now this makes perfect sense when you are trading with the tribe, but what about entrepreneurs? I suggest adding an architect schematic for a market stall or hut where craftsmen can store their goods and place them for sale. The stall/hut will only accept the local currency, meaning if someone comes in with another tribe's currency, they must first exchange it at the totem pole(if there is a global currency, obviously that wouldn't matter, but judging by an answer in the FAQ "ability to set a tax rate based if the tribe has a chosen currency" I presume we can get our own custom currency). The town would also set a sales tax that applies to all market stalls and is added to the price. This would allow for a more free market atmosphere as well as a more immersive environment.
Another piece to this idea is the ability to assign co owners to buildings. As a co owner you have full reign over the structure as if you owned it, but the full owner may come in and remove you. This would open the door to renting, allowing market stalls and even huts to be leased out.
Of course, with this we would also need actual owners. Right now it appears the game is set up in more of a socialist manner, ie the tribe owns everything in its sphere. If this is the case I would suggest changing this so that houses are owned. If this is not the case, ignore these last sentences. I'm not 100% sure because I havent built anything beyond tents, but even those I'd like to see it where the area under the tent or shed is owned and stuff can not be dropped/picked up unless you are the owner. Basically like your house is your personal tribe space in a way.