Location Targeting Your Facebook Ads in Australia

Location targeting is to target your Ad to the customers in those right Geo locations. You can target your Facebook Ad to particular locations by State or by Cities or Everywhere in the country (Australia).

Location Targeting - Facebook Ad

You can also include cities within 10, 25 or 50 miles for displaying your ad. When choosing your right locations for your ad, Facebook provides possible estimated audiences as per the locations.

Read more about Targeting Options

Campaign Cost and Budgeting in Facebook

from https://www.facebook.com/help/?page=219791638048948

There's no set cost for ads or sponsored stories, and as an advertiser, you can control how much you spend for each campaign by setting a daily or lifetime budget. 

When you run your ad or sponsored story, you will be charged either for the number of clicks (CPC) or impressions (CPM) your ad or sponsored story receives. The amount that you are charged will never exceed your daily or lifetime budget, and there are no additional fees associated with running ads or sponsored stories on Facebook.

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