Walking is Economical

So after clocking nearly 30K in about 12 hours I can tell you that you can save a lot of money walking places. We combined subways, ferries, trams, busses and cable cars and still managed to walk that much.

By avoiding the convenience of 7-11 on every corner and seeking out an actual grocery store, the fruits and water were way better price. 

Currency exchange is tricky. Most banks won’t deal with you if not a member and you have foreign currency in hand. Rates vary wildly from exchange place to exchange place. The plus of bringing some US dollars is you avoid the ATM and possible bank fee per transaction. Shopping around for a good rate paid off.