This is actually nothing special but probably best for beginners.
Ok once you begin battling and earning money, I highly suggest buying a lot of Copper Stocks, (You can buy them when you start) once you buy a lot then start buying Weapons, and Armour, once you reach level 7 you Unlock Nickel Stock (1,500 yen)
just make sure you dont load up on one type of Stock because you can only own 200 of them, if you have try selling some then buying some, I own 200 Silver Stocks and I get 100946 an hour!!! But i'd be earning more i just have powerful Items
In fact i beat the Los Angeles Boss under 1 minute! because i have so many spells and items!