if you have the patience, i suggest getting 4xcut because that is a godly materia. mime too, but since ur not into the chocobo stuff, then you don't really need it i guess.

you can find the double cut materia in the sunket gelnika. it's in an inlet south of costa del sol.

in the north cave, there is a marshy area. with w-item, you can get 99 elixers if you know how to work the glitch.

now in the marshy area, you'll encounter magic pots. give each one an elixer, and then just attack them. i suggest equipping cloud with the apocolypse (assuming you beat ultimate weapon) and putting the double cut(2xcut) materia into a slot in the apocolypse. this way, you should gain 3000 ap for each magic pot you kill. (sometimes they come in groups of two, resulting in 6000 ap)

there are also lil bouncy red balls called "movers"
they give a lot of ap, but no experience. you don't need elixers for them, just attack em, they aren't hard.

it takes a long time but it's easy if you have w-item and apocolypse.