For jobs teaching English (it's not really a career choice unless you end up getting a proper teaching degree or happen into something special) check out www.gaijinpot.com it's, despite the name, one of the most credible sources for English teaching jobs. For universities, public universities in Japan are incredibly cheap when compared to universities in the US. Tuition for the university I went to was less than 5,000usd/yr (a tenth of what I paid in the us/year for undergrad) and there are scholarships a plenty. Check out the MEXT scholarship or JASSO. I ended up getting both which paid for my living expenses as well as school. Like I said, working part time on top of that I was living very comfortably. So, going to school will grant you a very affordable apartment, gym membership, very good intensive Japanese lessons, an education, friends, the chance to work up to 28 hours a week, and if you get a scholarship, spending money, on top of the education of your choice.

Search for the G30 program. There are a bunch of public universities here that participate in G30, which is made for foreign students, in English and it's very well funded.