New customers who take up 4G mobile broadband plans will get a 10% discount for the first 24 months on the $65 4G Internet Lite and the $75 4G Internet Everyday plans on month-to-month or 24-month contracts.
Pre-paid customers can buy a $30 SIM card for $5 and receive a $20 discount on pre-paid handsets (excluding X Lite) when they purchase online.
The pre-paid discount will include a $30 recharge, with expiry and inclusions depending on the rate plan.
Optus is also trying to attract people to buy its accessories range, with an offer of $59 off on the Galaxy Buds+.
The device discount is available to consumer and SMB customers, apart from TechFund and Fleet, between 27 November and 6 December who sign up and stay connected to an eligible SIM, Data SIM plan or Connected Watch plan with a 24- or 36-month device payment plan.
If either plan is cancelled, the credit will not apply to any outstanding amount with a limit of five redemptions per customer.
Buy now, pay later firm Zip says it is offering the following to its customers between 27 November and 30 November:
EB Games: Those who buy a Nintendo Switch online at EB Games via ebgames.com.au using an active ZIP Pay or Zip Money Account will get a limited Nintendo Switch Bundle including one free game.
Amazon: Those who shop on Amazon.com.au or the Amazon Australia mobile app using a Zip Pay or Zip Money account will get 10% credit back (up to $50) on eligible purchases to your Zip Account.
Tommy Hilfiger: Customers who spend $150 or more online at Tommy Hilfiger using a Zip Pay or Zip Money account will get $20 credit back to their Zip Accounts.
Calvin Klein: Spending $150 or more online at Calvin Klein using one's Zip Pay or Zip Money account will get one $20 credit back to one's Zip Account.
Rebel Sport: Anyone spending $150 or more online at Rebel Sport using a Zip Pay or Zip Money account will get $20 credit back to one's Zip Account.
Appliances Online: Shopping online at Appliances Online using a Zip Pay or Zip Money account will earn 20% credit back (up to $120) to one's Zip Account.