You should do this trophy in conjunction with Tycoon, since you will need to spend a total of 500,000G from the shops in order to unlock it. Spending that amount can be a bit hard, since you might not know what to buy (see Chowhound for some extra spending tips), but if you continually farm money and upgrade your weapons and armor with upgrade spritnite, then this shouldn’t take too long. You can keep track of your progress in the Moon Memory.