You may have not realized this, but magic as built in to AD&D 1E. Yes, I know, you might have missed the concept entirely. Good thing I pointed that out huh? This could change the whole game for you now.
Seriously though, I get to talk with a lot of folks who act like magic in the game is a bad or rare thing. it's their game, they can run it however they like. I have no problem with that. I just don't understand it.
Here you have a fantasy game with magic just oozing out of every crack and crevice in the book, just begging to be put to use. Some DM's act like the merest mention of magic is a wicked thing.
Not here. I let the magic flow freely. It starts with my whole outlook on the game world. My world i not just some replica of a medieval map guided by historic ideas of medieval life and technology. Nosirree Bob.
My world is more like an alternate universe in which magic takes the place of "high" technology. Magic is everywhere and at various scales or levels of influence.
I do divide magic into two types. There is "Common" magic and then there is "Divine" magic. Common magic is magic made or done by people. Common magic is, well, common. You can find enchanted items and spellcasters in most places.
Divine magic, on the other hand, is rare and doesn't just "happen". This is the power of the deities. Most often turning up, if and when they ever turn up, in the form of Artifacts and Cursed items.
You can find enchanted items like weapons, armor, rings, cloaks, etc.. in urban and suitable places everywhere. the more powerful the enchantment, the less likely you are to find it. This is usually because most magic users die off before they reach the levels required to make the really potent magics.
If PC's want to find certain enchanted items, again things like weapons, armor, etc.. they really aren't too hard to find. They get more expensive the more powerful the enchantment on them though, due to that less commonly found powerful magic user surviving long enough.
A party can walk into most towns and find a magic shoppe or magic user in residence who can help them obtain the more common types of things.
Artifacts are rare, exceedingly rare and these usually require a quest or the like to obtain. maybe. Why? Because Divine magic is insanely powerful and doesn't become less powerful as though it's batteries ran out or something after so many uses. Once the item is touched by divine power, it stays that way.
Just a little something about magic in my world I thought I'd share.