[Sangetsu]

Before judging your monthly pay you have to take into account that you are probably going to be a part-time worker limited to working 29.5 hours per week. This is usually the case with foreign workers as the company won't have to offer the additional benefits that full-time workers get. Any hours worked past the 29.5 you are scheduled for will result in overtime pay.

For part-time work, 200k yen per month is about what new-grads get when starting with a company. You should expect a raise each year with each new contract.

As for monthly expenses, those are very relative. But, here is what I figure to be the best average:

Food, 30,000 yen per month,
Cell phone, 4500 yen per month,
Internet, 3500 yen per month,
Gas, 3000 yen per month,
Electricity, 5000 yen per month,

Transportation is generally reimbursed, I don't know any companies who don't pay for at least part of an employee's transportation. If you are traveling 15 kilometers per day, your train fare is probably going to be around 500 yen per day. For those who commute 30 minutes or more, many companies will also compensate for commuting time.