As DOOR ONE RIGHT said, you can get by on as little or as much as you want.
I have been to California and Hawaii for weeks at a time each year for the past 5 years and believe me - you can spend well over your budget, or get by on $30. a day - depends how little or how much you want in your pocket at the end of the week. Food (and most things) are that much cheaper over there and who wants to spend your lay over (and money) sitting down to 3 course meals every few hours.
From what I understand, the US$125. per night allowance is paid into your bank acc at the end of that 2 week pay period, so you will need to pull money out of your acc to have cash while in the US.