My target monthly budget for this trip is $20/day.  I started travelin January 23 which gave me 9 days of travel in January or a budget of $180 (This does not include my flight to Cancun, just travel once I arrived).

My January spending was:

Transportation: $21.72
Food:  $54.06
Lodging:  58.15
Entertainment:  $8.16
Misc*:  $21.27

Daily average:  $18.15

Monthly Total:  $165.35

Budget difference:  $16.65

* This includes buying a new dress and some antibiotics.