As a teacher in Macau you should expect around 20,000-30,000HKD per month, sometimes not including accommodation. Note, Accommodation is expensive in Macau and you need to budget at least 10,000HKD for a reasonable place.
As you are in the gambling city of Asia it is very easy to get carried away. If you think you'll have a problem with controlling your spending in this environment we would urge you to consider a mainland city such as Guangzhou, Zhuhai, Foshan or Shenzhen where you are just a few hours from Macau.
(20 hrs per week, Mon - Fri): 20,000-30,000HKD /month
(25 hrs per week, Wed-Sun): 20,000-30,000HKD /month
Bus Fare: 10-20HKD (Anywhere in the city)
Taxi Fare: * 15HKD for the flag-down fare
* 7.5HKD per kilometer
Eating out (Chinese restaurant): 100-500HKD / person
Eating out (Foreign restaurant): 150-500HKD/ person
Apartment Cost: (Non-Central, 2 bedroom, new) 10,000HKD /month
(Central, 2 bedroom, new) 20,000HKD /month