My idea was simple: to craft an item from bought ingredients and then sell it for higher price than it cost me to buy ingredients and craft the item.
I found three such items that can be crafted with positive profit:
Hats are more profitable than simple coats and made from same raw materials, so you can just ignore simple coats and craft hats instead.
In order for hats to be profitable we need cheap fabric. And we will be able to get endless supply of cheap fabric if we will buy the Bitterroot farm. After that the farmer will sell us 1 unit of fabric for 175 gold.
To produce flash grenades we will need beer. It's sold in the Aldlyn Bar (among other places).
We can buy the grenades recipe from the blacksmith of the elvish village (AKA Ebron).