How do you get easy money fast harvest moon magical melody?

ask the Harvest Sprites to do fisahing at the beach you get tonns of money!!!

the best time to fish is in winter as you always get...:100000000

true fact!!!

and then thomas will give you the private island on the 1st off spring...well...that wasnt your question :D
If you are a cheater: During winter, employ your fishing Sprite team for 1 week. Sometime during that week, you will wake up and magically have 1 billion dollars exactly.

If you want to earn your cabbage: Plant as many crops as your watering team can water. Crops are worth a lot of money.