Community Notice Boards for Free Advertising
An effective offline advertising method is to put ads up on various community noticeboards in your city. It takes a while to find them all, but when you have done so they are the gift that keeps on giving. They do get torn down and covered over so you just have to keep reposting them occasionally. But if you keep at it so that you have dozens of them up at any one time the calls will keep trickling in.
IGA Supermarkets
It's hard to know where they'll be of course. But a great place to start is with the IGAs. These are usually in the form of a grid into which you can slot a written card (which they supply). Some of them also have the traditional ones that you can pin or tape bigger tear off tab ads to.
Many but not all IGAS have them. So it's a good idea to call beforehand to check. You can find the contact numbers and addresses via the store locator on the main site.
Since returning to Sydney in late September 2015 I've confirmed that the ones listed below currently have noticeboards.
Leichhardt, Annandale, Summer Hill, Birrong,Yagoona, Bankstown, Dulwich Hill, Ramsgate,North Strathfield, Crows Nest, Port Botany, Mascot, Alexandria, Haberfield, Lillyfield, Drummoyne, Sutherland, Jannali, Mortdale, Penshurst, Arncliffe, Turramurra, Wahroonga, Mosman, Revesby, Bexley, Hunters Hill, Freshwater, Balgowlah Heights.
Coles Supermarkets
These are much like the IGA ones. They usually have their own branded cards that you can write your ad on. And there are often place holders for business cards, etc.
Broadway, Maroubra Junction, Bondi Junction (Westfield), West Ryde, Eastgardens, Manly, Balgowlah, Waringah Mall, Hornsby, Revesby, Epping, North Parramatta, Edgecliff, Randwick, Surry Hills, Oatley.