There are many stores found in the game, all inside towns.
Each store is of a certain type, which will determine the inventory that it stocks for sale. Stores only acquire inventory three times over the course of the whole game:
Stores will also buy any item you choose to sell. In practice, this is only useful in your first few games, before you have unlocked the Transmogrification Chest at birth.
In addition to the standard inventory for each store type, there are a few special features in certain stores: