Go to the ATM for your bank, so you don't get charged extra money. Keep any minimum balance in your account, so you don't have to pay a monthly fee. They don't allow you to switch to another long-distance company. Instead, use a pre-paid calling card to make international calls. If you use pre-paid calling cards, it costs only 12 cents per minute to Japan.
Some phone cards are expensive.
Choose a phone card carefully. I have saved a lot of money by this method, and I really recommend this to international students. Ask a friend to cut your hair.