I am going to live with my japanese boyfriend and his family but..?

Question:

i am going to japan for 3 month in order to spend some time with my japanese boyfriend. Till now i lived on my own, but now i have no money (i just come back from japan after 3 months of attending a language school in tokyo) so i'm saving in order to come back to my boyfriend from November. since this time i cannot afford an apartment in tokyo ( even if it would cost 500.000 yen a month i couldn't afford it because i have still only 3 months of work before the departure) i am going to live with him and his family (his father and his bigger sister). and off course i am willing to pay his father a certain sum of money. the house is in Saitama, an hour from tokyo. and not really big. but i'd like to pay all my expences (my part of the house's bills) and of course more because i'm a trouble (even if he says that there is no problem and that even to don't pay it's ok). i'm going to live in the same room with my boyfriend so i'm not going to occupy an entire room. Which is the proper sum to give them?

Answer:

I think 20,000-50,000 yen per month is reasonable in your case. But it's negotiation between you and them after all.