Arcane magic is rare. Even the primal powers will turn a few eyes if used in public and, in the wrong areas, could be enough to provoke hostility. This also means that most of the magic items listed in any of the books will not be available. There are superior crafted mundane items that will confer bonuses or perhaps even have quasi magical power – like lighter chainmail.
Alchemical items would be available in larger cities, but you’d have to have connections or make a decent Bluff check, in order to purchase them.
Healing potions are created by priests of The One God. These would be available in most cities, however, if the shop owner doesn’t know you, you’ll have to prove that you’re not going to abuse the potion or use it against any followers of The One God. If you’re going to pursue monsters or magic users, then the shop owners would be more apt to sell you them.
The Church priests also create other items which are magical, but the power source is divine, most of which are protective.