This is pure speculation on my part. This is a start on a discussion on how your actions affect the world. Also its a narrative...
Lets say you have been out and about adventuring. You have picked up quite a lot of crafting materials and you figure to make a bunch of swords and/or armor. You head into town and go to your crafting station (forge/woodworking table/etc.) and you make a nice piece of armor. (lets call this piece "Omega13") You see that you can make several of the same armor with your supplies and you do so. You then sell your excess stock of new armor to the local merchant.
You go about your adventuring lifestyle to other far off lands and places. You finally come back to the area around the town/city where you made your awesome "Omega13" armor. before you enter the town you are attacked by some bandits. You easily dispatch them and as you are looting there bodies you find one of them is wearing "omega13" armor.
The above is an example of item economy. Where if you make a bunch of items other people in the world are going to buy it and use it. Another example would be that items you made and sold in one town cheap can be found in another but more expensive. Though both could be true. And I'm not saying this is absolute. The bandit probably couldn't buy it but looted it himself off another traveler.
I could go details on how much an item is worth vs how likely it would end up in whose hands but that would be inviting some flames my way. Discuss and I look forward to Skyrim.