Which company provides the cheapest mobile phone subscription?

@HI Donald, this was very annoying for me the first time i came to JP either, especilly the services accompanied with the SIM card you choose. I suggest you to go with a Japanese friend if you can.

Fortunately, I think you should go to GTN in Osaka or Ikebukuro or Shinjuku in Tokyo for cheap services. This is really helpful 'cause it meets foreigners' needs.

They also employ foreigners so they might speak English and other languages as well. You may want to use a sim-free mobile because the costs will be cheaper. The monthly cost i currently pay is around 3000 yen. This is the link https://www.gtn.co.jp/en/

Hope this helps :)