What are the most expensive costs in Japan?

Housing is definitely the most expensive cost in Japan, particularly in big cities. Expect to spend 30-40% of your income on rent in Tokyo, where a 1-bedroom apartment in a central area can easily run ¥100,000-¥150,000 ($700-$1,000 USD) per month. Initial move-in costs are also high, often requiring 4-6 months' rent upfront for "key money," deposit, and agent fees. Dining out is another significant expense. While convenience store meals are cheap, a casual restaurant dinner can cost ¥2,000-¥4,000 ($14-$28 USD) per person. Transportation, especially bullet train travel, adds up quickly; a one-way trip from Tokyo to Osaka is around ¥14,000 ($95 USD). Public transportation within cities is efficient but not free, averaging ¥500-¥1,000 ($3.50-$7 USD) daily for commuters. Healthcare, while excellent, can be pricey if you're not on the public system; a doctor's visit without insurance might be ¥5,000-¥10,000 ($35-$70 USD). Groceries and utilities are generally reasonable, often cheaper than in the US or UK. Focus on budgeting for rent and transportation, as those will impact your finances the most.