Australia's NBN providers are locked in a price war of sorts at the moment, with a handful offering discounts on the highest speed plans. It's presumably to accelerate adoption of NBN 250 and 1000 plans, which are still relatively new. In addition to its previous discounts to its NBN 250 plan, Superloop has another tempting offer: 250Mbps speeds for people who sign up for NBN 100.
Basically, if you sign up for the provider's NBN 100 plan right now, you'll get an automatic upgrade to NBN 250 (providing your connection can handle it). That will last for three months, and it coincides with a current six month discount on the NBN 100 plan, which is AU$74.95, down from AU$89.95.
So in a nutshell: for three months you can get NBN 250 for AU$74.95 a month, which is pretty sweet: that would normally cost you AU$119.95 without any discounts. After three months your connection will automatically downgrade to 100Mbps speeds.
If you want NBN 250, Superloop is currently offering its plan for AU$99.95 a month for the first six months, after which you'll get it for AU$119.95. Whether you're keen for a 250Mbps connection or don't think you need it, you can sign up temporarily and, I dunno, download your entire Steam backlog while the going is good. There's no fixed term contracts, after all. For more price war shenanigans, here's the best NBN plans for gaming in 2021.