If you already have one character, create another one and talk to Tom Nook. He will talk to you and offer you a part time job. Finish all of the tasks he gives you and he will give you 12,000 Bells. Drop the 12,000 Bells on the ground in front of your house, then get your other person and collect the Bells from the front of your house. Afterward, kick the extra person out of town.