While Belong has a long running deal with all customers to refer a friend, they have doubled the offer.
$40 off your first invoice if you join with a referral code before June 30th. Both the "friend" and the account holder will receive this credit. I have not included my referral code here, as you can use the links to randomly select a fellow ozb user's code.
Belong is a great way to get your internet connected if you have no active line - there are no charges and you can select no contract options, pay one month and the modem cost, cancel, and your line will be active - Beats the $300+ Telstra try to charge.
NOTE: Belong will give you the "rest of the month" free upon activation, so a good idea is to apply for this service so that it activates around the first few days of the month - that entire month will NOT be invoiced, and this means you get ANOTHER month free! Belong bill on the 1st of every month. To give you a rough guide, it took 5 business days from day of sign up for me to receive ADSL2+ - I had no active line at the time.
Just be aware with Belong that their default NBN speed is a copperific 12/1. You need to add a "speed boost" pack for more.
If you're going with ADSL this isn't a factor. For reference, their 1TB ADSL plan is comparable in value to Internode's 1TB Naked @ $70.