I find that using the Yellow Computer to get the max health buff move, "Health Stand", is actually the best option for most of the game. It isn't JUST a max health buff -- it actually heals you to beyond full HP when you use it! Of course, the ten-turn cooldown is harsh, but more than fair in exchange for granting you freedom from healing sodas forever. By the time most enemies can wear down your health completely, you'll be ready to Health Stand again. Grinding up enough cash to both upgrade the equipment shop and buy the Yellow Computer is the hard part...