Amaysim's 2GB and 30GB mobile plans are on sale for $5 and $10 respectively.
Combine the 30GB plan with Cashrewards or ShopBack for $21 cashback (Edit: $5 mobile plan is not applicable for cashback).
Their billing period is 28 days, not the full calendar month.
Remember to turn off auto renewal at their account portal. Their normal prices are pretty poor value.
Uses the Optus network.
Both ShopBack and Cashrewards only allow one Amaysim cashback per account. Both state they only allow one account per person in their terms and conditions (Cashrewards under 2.3.1 and ShopBack says one per person and phone number under section 2). Both are also very aware of OzBargain and likely have extensive experience dealing with people who try to take it too far. I wouldn't try anything cheeky unless you genuinely believe you are capable of fully covering your tracks.
Anyone else having trouble? When I click through to Amaysim site with Cashback it ShopBack it buy now it directs me to an outlook login page…