There are two items that you can buy/find that will replenish MP. The first is Magic Water which can be found in quite a few places:
Batsureg (500g), Bloomingdale (500g), Gleeba (500g), Gortress (500g), Porth Llaffan (500g), Slurry Quay (500g), Swinedimples Academy (500g), Upover (500g), Wormwood Creek (500g), and Dourbridge (2500g). Jinkster (#056) (steal/win, common, 1/32), Lunatick (#032) (steal/win, rare, 1/64), Firespirit (#010) (steal/win, rare, 1/128), and Magus (#043) (steal/win, rare, 1/128).
The second is the more-potent and more elusive Sage's Elixir which can be found:
DQVC (price and availability varies), Grotto chests (Ranks 7-10), Freezing fog (#177) (steal/win, rare, 1/64), and Fowleye (#291) (steal, common).
Beyond that, as bengra08 mentioned, there are certain items that will replenish MP in battle and some that will even replenish it as you walk around. Additionally, don't forget that making a physical attack with a Wand-class weapon will drain MP from the enemy as well as doing damage. Good luck!
(Expert) - 9 years ago