Real estate agent commissions in Victoria generally range from 1.6% to 2.5% in the city and metropolitan areas and 2.5% to 3% from the metropolitan area outwards. The commission rate is not set by law so you can negotiate.
When I last sold a house (in NSW) I offered the agent a bonus % (.35% above the standard from memory) if he achieved a certain price - and negotiated .25% less than standard if he didn't achieve my price. He achieved my desired price!