In Guardia Forest, you can build up plenty high and make the game easy from there on out. This would probably be best to do when you get Marle. Keep on fighting the Hetakes, Beetles and Avian Chaos' and buy supplies with the money, with the one exception of the Iron Sword. Once you're loaded (buying Tonics is not recommended, as the creatures give you a Tonic every battle pretty much), save up for the Lode Sword. The Lode Sword will be incredibly useful, and then once you find the one in Guardia Jail and Lab 16 you can get 2000 a piece for them.