[sarasi]

It's definitely becoming more common for unmarried couples to live together, but the further away you are from the main cities, the more conservative the landlords get. I lived with my then-boyfriend, now husband for 4 years before we got married, it was not an issue with any of the Tokyo landlords or agencies we approached. We are now living in a government-run housing estate and to move in here together you do have to be legally related, so if you are not married you have to sign a paper saying you are engaged and plan to marry by a certain date.

I have a lot of Japanese friends who are not married but living together though- things have changed a lot in the last decade or so.

To the OP, with no bachelor's degree and no source of funds to support you while studying, I'm afraid I have to confirm there is no way for you to get a visa to stay here long term- all you qualify for is a tourist permit at this stage. I'm not sure why you thought that going to college in Japan would be less costly than in the US as this is very much not the case. I agree with Nyororin that in Japan people without reasonable Japanese skills will not usually even be given a job as a dishwasher as ability to communicate with co-workers is considered very important here, and few people speak good English, especially in that kind of work.

As someone said above, start planning more long term. Find out more about schools and jobs here that are open to non-Japanese, and what visa options are available. Forget citizenship for now- practically speaking you will need at least 10 years in Japan before you can even consider it. Japan does not recognise name changes unless they are made in your country of citizenship, so you would have to change your name in your country of current citizenship to do this.