Price Ranges are only used in the "Traditional Search" facility.
This will allow you to customise the drop down list when the buyer needs to select the price range he/she is interested in.
To manage these log in and navigate to the Administration Section » Dashboard » Manage Property » Price Range
This is a simple screen to change the type or add a new type.
When the user selects a minimum and or maximum price range the search results will display all properties falling within the range (inclusive)
If you do not define a price for a property a value of "0" will be used and it will be filtered as POA by the search engine.
Search results without either a Minimum or Maximum value will include POA properties