Sim plan in Japan

I have checked this site and found out that i can use my unlocked iphone 5 A1429 in japan.
But the prices are too expensive. Can anyone suggest me any cheap SIM providers? Also, i dont want voice messages, so when i buy a sim card can i omit it and save money? I just want to call..dont even need data.. Japan has wifi in most of the places.
So i need sim card just to call..can this be possible?

Softbank sim cards should work for you then. You can either get a prepaid or rental sim depending on your calling needs and how much work you're willing to go through to get it set up:

http://www.softbank.jp/en/mobile/
http://www.softbank-rental.jp/e/