EvanNave55
Explorer
I'm afraid you are making it out to be more difficult than it really is.
All you have to do is set up prices for items and then adjust the gold you hand out to your player's. A +1 sword could cost 4000. Now just setup your adventure to where a party of 4 players find a combined total of 16,000 gold during a span of level 1 to 4.
This was just a quick two second example I came up with on the fly.
It's not complicated nor does it half to be. The only way it becomes hard or impossible is if you make it that way.
Making one magic item with no context? Sure that's easy but when you add in all the other items in the game it becomes exponentially harder. Two items- twice as hard. Three items four times as hard. Even ignoring all the mundane things in the game there's still maybe 200 magic items. That means the difficulty becomes 1.6 followed by 60 zeros.