In 5e?
Xanathars has advice for how player characters can create magic items. Generally the cost is the same as whatever the cost is. Upgrades cost the new minus the earlier.
No spells needed.
A Fighter can make a magic item, which makes sense if one thinks of certain katana makers and so on.
However as DM, I dont like buying or selling magic. So I would require ingredients that are symbolically relevant that may or may not be hard to find.
As DM, I also want skill checks like Arcana or Nature and especially Tool checks like Smith if making a magic sword.
Generally, I would make a sidequest out of putting the proposed magic item together, along with skill/tool checks to determine success.
And of course, the DM needs to agree the level and thematics of the item are appropriate.
As DM, what makes magic feel magic, is having a personal relationship with the magic item. The magic item will a have part of the personality of its creator within it. The ability to attune a magic items depends on whether the player is carrying out an intention, if any, of the original creator. This mostly for special items, tho, that are powerful and thematic. Common items can be routine and mainly for the sake of convenience.