how to stay rich in bells while ‘paying ‘ debts to tom nook

every one on my island always asks me, ‘WOW how are you so rich yet you have payed off all your debts’. Now i still sometimes debate whether i want to tell them or not, i know they might try to steal my method but im going to share it anyway. Tom nook is a simple fellow, he likes two things, bells and balls (sports). If you find a way to incorporate those things into your payment, you might even be making money.