Optus now offers 4G for its prepaid customers, as long as you have your own 4G phone compatible with the telco's long-term evolution (LTE) network.
Plans start at AU$30 per month, and mirror the prepaid plans already in the market from Optus, with the lowest plan returning 250 minutes of calls, AU$30 credit and 500MB of data each month. 4G prepaid customers also get unlimited use of social-media sites Facebook, Twitter, Foursquare, LinkedIn and MySpace.
Finding a compatible device will be tricky, though. Both Optus and Telstra have 4G networks operating on the unusual 1800MHz frequency, meaning that most of the phones in their range are custom ordered from the manufacturers to include the necessary radios. Until Optus ranges prepaid 4G handsets itself, you will need to look for a reputable online store to sell you one.