The more friends you add, the more coins you will receive. You will get some coins each time your friends' Miis ask you a question. And the more friends you have, the more questions you will get. Each time you answer a question, you will earn coins. Log in daily to earn free coins. Play the Miitomo Drop mini game. Although you will not get coins directly from it, you will have a good chance of receiving free clothing. This saves coins that would have been spent purchasing those clothes.