Mist Potion

A Mist Potion is a consumable item in the Golden Sun series introduced in The Lost Age. Like most consumable items, each party member can hold up to thirty mist potions in a single inventory slot. When used, a mist potion restores 300 Hit Points to all party members—but if in a battle, it only affects the four currently fighting Adepts. Mist potions can be bought for 9000 coins and sold for 6750. They are considered Artifacts, meaning they can be re-purchased if sold or dropped.

The Lost Age Mist Potions
In Golden Sun: The Lost Age, a single mist potion is added to item vendors' Artifacts section the first time players visit Contigo and Loho. Also, a limitless supply of mist potions can be bought from the item vendor in Prox, curiously appearing in the shop's "normal item" stock despite being an Artifact.

Mist potions are dropped by Grand Chimeras and Ghost Armies.

Dark Dawn Mist Potions
In Golden Sun: Dark Dawn, a single mist potion is added to item vendors' Artifacts section the first time players visit Border Town, Yamata City, and Tonfon.

Mist potions are dropped by Kobold Kings, Earth Lizards, Chimera Mages, and Mad Demons.

Analysis
Mist potions are the only consumable items that restore HP to multiple party members at once. While this does make them useful, it's up to players to decide whether the staggering nine thousand coin price is practical. To compare, vials restore 500 Hit Points—almost twice as much as mist potions, but only to one character—and cost a mere 500 coins, and normal potions (restoring all HP to one ally) only cost 1000 coins. This makes mist potions the most expensive consumable item by nine-fold. Many players may be better off not investing in them until after optimizing their equipment setups.

To further cast doubt on their practicality, mist potions are only the second most effective group healing technique. The Pure Wish Psynergy restores 400 HP per Adept and only costs 20 Psynergy Points, a low number during the later stages of the games.

But, on the other hand, even after manipulating the party's classes, only a few Adepts will possess the Wish Psynergies, whereas everyone can carry mist potions, making them good backups for when a designated healer gets taken out. Cash is often plentiful at this stage of the game too, and there is little else to buy, so it might be a good idea to stock up on mist potions before the final battle.