In Tokyo alone, there are about 150,000 restaurants. Japanese, Korean, Chinese, Thai, Vietnam, Italian, or French cuisine… You can eat every kind of dish. Many restaurants adjust their flavor to Japanese people’s liking, so if you miss your country’s taste, you should ask those from your country for recommendations. In addition, you will not have a difficulty finding food, as convenience stores open 24/7 and sell small meals, like sandwiches. On the other hand, vegetarians may have a trouble, since Japanese dishes tend to use broth from fish. There are fewer restaurants that can accommodate particular dietary, such as gluten-free options, so if you have any limits on your diet, I recommend that you do some research beforehand.
The following costs are estimate for each meal:
Breakfast, 500 to 1,000JPY (4.6 to 9.1USD)
Lunch, 800 to 1,200 JPY (7.3 to 10.9USD)
Dinner, 1,000 to 5,000JPY (9.1 to 45.4USD).