Earn loads of money by selling various objects. Buy some paper from Tom Nook, then click on the paper, as if you are writing a letter. Keep going along the adresses, till you get to 'Your Future Self'. Select it. Write whatever you want! Confirm it, so it turns blue. Next click where your money is displayed in your inventory and withdraw all you bells. Drag it to the letter and send it in the Town Hall. Send it for a few months, or a year (maybe even your birthday or chistmas), then, when you recieve it, you will have much more money, a nice surprise, especially if you find it hard to earn bells!