[MMM]

Plan on spending more than 10 dollars a day on the train to safely budget.

Ueno is a nice, central location. ata reasonable price. Think about what you might lose in train fare and time if you are further out (I am not familiar enough with Asakusa to be able to tell you it is better or worse).

Get a travel guide. 19, a month by yourself, away from your family...this will be a mental journey, as well as a physical one. I did something similar when I was 16, but I was staying with a Japanese friend and his family, but my first trip to Japan was abot 3 weeks, and I felt like I was in the deep end of a pool and forgot how to swim a couple weeks into it. Prepare yourself mentally for that possibility. I have seen it happen to people much older than you. I guess that is culture shock.

Why do you think you need a phone? If you want to call home, use phone cards and pay phones. I can't remember if you can call collect, though...

Finally, get a travel guide...or three. Tokyo is a BIG city with tons of secrets you have PLENTY of time to discover, but you aren't going to find them without a little help. Imagine, you are on a treasure island. Do you want the map to the treasure, or not? You are NEVER going to find it without the map, so might as well invest 20 bucks in a couple travel guides to help you find some cool and interesting (and delicious...and necessary) things.