Unexpected costs for study?

I’m considering attending an international uni in Japan’s countryside and am doing comparisons between cost of that uni and the uni’s in my state, but am wary due to the possibility of hidden or unexpected costs.

Has anyone who studied or is studying in Japan now run into these unexpected costs or just costs that you didn’t intuitively assume came with the whole package?

Edit: I realized there wasn't much information given.

– The Uni has dorms I'd be staying in with kitchens so I'd either have to buy food or cook with groceries.

– It is in the countryside, so probably not as expensive as Tokyo or something

– I'm planning on tutoring during school for extra cash (about $30 an hour) as well as doing some judging for my past extracirriculars which could go up to $75 an hour. I would love insight on wether this could be feasible for basic expenses like food and other emergencies.

– I am walking to school so little to no daily transport fees

by MinuteDesk9626