Be careful about your spending.
Transportation and food, in my opinion, are more expensive than it might seem when you first get to town. It wasn't until I was burning ¥5000 per week with my Suica that something was wrong with my transportation costs. Likewise, you could easily reach ¥3000 per day on food since you'll inevitably be hitting the vending machines and may want a snack or two while you're out.
http://www.hyperdia.com/cgi-english/hyperWeb.cgi
Use that link when needing to take the train. It has the shortest, cheapest and fastest routes.