Man people need to relax in this thread. The OP is asking how to "abuse" the rules to make money, this is the very premise by which this thread is founded on, no need to come down from on high and release your moral judgement. Its up to them and their DM to decide if they want to allow anything, the OP is simply looking for ideas. So people just chill out.
So the DM can either go with the more "mundane" economic concepts, or the disruptive ones.
Mundane
In this model, sure you can instant create stone, iron, fabricate plate mail, etc.....so what? This already assumes a world that has that implicit in its economy. You can join a stone masons guild (which already takes wall of stone as their raw material and works it from there). You can get in line with the other 3 wizards that offer fabricated plate mail for clients that are willing to pay the premium for "I need it now"
Aka your not getting rich off your talents here, the competition just prevents it. You can make a very nice living (I would still expect such a wizard to live an Aristocratic lifestyle), but your not going to break the world economy.
Disruptive
In this model, you are bringing the golden goose to the table, and in doing so destroy whole economies.
In this model, you are going to get rich really quick. But then the "real game" begins, and in this model the DM is likely using your "abuse" as a plot point. Ok you tipped over the apple cart, and now the rest of the world is pissed. The game is no longer making money (that's the easy part), its now how to survive and keep what you've earned.
So a few ways to go here:
- Wall of Stone = Unlimited Stone Mining
- Teleport Circle = Permanent Transportation Business
- Fabricate = Ultimate Crafting and goods provider (become the army's weapon manufacturer!)
- Create Food and Water = Find a miserable desert and sell your goods at a ridiculous markup (bonus points for doing it in a blue dragon region where water gets spoiled).
- Dominate People and get them to sign over land and things to you.
- Heroes Feast = Ultimate Restaurant
- Plant Growth = Ultimate Farmer