This is the beginner quest in the rook's gambit tavern. First, start by getting the quest and entering the quest! When you reach the room with all the barrels and boxes climb to the very top, there is a chest hidden back there in the corner. Open it! free heal potions/kits, repair potions/kits. Get everything from the chest then Recall. Join someones' party or invite someone and wait until they join. Logout, log back in, talk to Euphonia again then enter mission and repeat.
(NOTE: This saves a bunch of cash and allows you to stock up greatly on some of the most needed resources to either assist your party or solo!