I have two concepts for NPC shops that I'd like to suggest. I think both of these are probably far-future if at all, but might be simpler to build than general real-estate ownership. I'm thinking of this as a starting point of course, it has some rough edges.
Idea #1: A consignment shop - Instead of (or maybe in addition to) selling a fixed list of items, the proprietor would sell items sold to them by players. For instance, you could sell tefusang hides to the proprietor, and he would charge other players for the same item. You would pay 1 % of your asking price up front, and you would get paid 90 % of the selling price, but not till the item is resold. (The one percent is to keep people from selling a mushroom for 1 million trias just to clog the list.)
I'm thinking it would be a sort of anti-auction, i.e. you specify a price for the item, and the price goes down 5 or 10 % a day until the item is sold - if not sold in one week, you could pick it up yourself - if not sold in two weeks, it gets thrown on a pile behind the store.
Idea #2: Player-rented NPC shops. Players could rent a shop booth from the guy in Hyldaa who collects taxes from people (I don't know his name but he already exists as an NPC - he doesn't collect money yet or anything.) The booth would be manned by a randomly rolled NPC - a salesperson - who would operate the shop on behalf of the player. All money would go to the player with no deduction, since they already prepaid the NPC his hire. If the player does not keep the rent paid ahead of time, the shop is abandoned and the goods are simply dumped on the floor. You could pay any amount of rent ahead of time. The price of renting a shop would be determined by supply and demand - if there is a maximum of 20 such shops, the rent for one day would go up by 1% whenever all 20 were rented, and down by 1% whenever less than 10 were in use. (Or some similar system.) A starting point for rent might be 200 trias per day. I'm thinking the shop would be open during a fixed interval each (in-game) day.
These shops would need to either be in an as-yet-uncreated bazaar area, or spread over the map (a few here and there in various existing areas), but I suspect a section of Oja is the most natural choice if they were concentrated.
Sw.