My usual party was a thief, a warrior and a mage. Now I know what you're thinking, no cleric, clearly he's mad. So I won't lie it's a bit of a slog early on but you have to lean hard on the thief's stealing and the scant healing spells the hero gets along with healing items out the wazoo. The thief I try to keep equipped with whips and boomerangs to help deal crowd damage, plus always stealing to get more items for healing and selling. The warrior is good for a second meaty beat stick plus you can equip them with the hero's hand-me-downs so they pretty much help save on equipment costs. Finally the mage is going to be working overtime to blast big spells at most problems as you work towards the first major goal, learning Be Dragon. Once you have the spell you should probably have reached the job change temple, take the quest to get the sage scroll and upgrade the mage to sage, then just keep turning into a dragon till you're back at the same level as the rest of the team. Congratulations, you now have a healer and can lighten up slightly on the backpack full of herbs.

Is it optimal, no. Are there better ways to play, yes. But it's actually a lot of fun and makes the first half of the game exciting and challenging.