Best operator to get japanese number with?

Hi, so I came to japan for a student exchage in Koyto and I need to get japanese phone number to later get a bank account to pay for the dorms and all that. Which operator would you recommend I go to to get this sorted out? I am mostly looking for something cheap with good deals on mobile data as I rarely need to make a call. My current plan with my operator in my home country is 5€ for 2 GB of data a month and then credit for calls and I've never paid more than 7€ a month in total. I wouldn't mind having a bit more data here in Japan as I need to use navigations and google thing a lot more often and I wouldn't mind paying a little more for it either but I'd still like to stay somewhere around 2000 – 2500 yen/month if an option like that exists.

My uni recommended GTN mobile and the prices seem okay, so should I go with that?

by fangirl004