This is one thing I really don't miss about Australia at all. NBN failure and the continued paying by GB. I have unlimited data on both my home connection and my tether-able mobile. I pay like $20/mo for the broadband connection and about $120 for my pretty premium mobile service. $140 doesn't seem that much at all, but there are a number of people who think my mobile bill is too high, but they usually have internet at work (I haven't been allowed on a work network in close to 10 years, because they're almost always PC networks or the computers are PCs provided, and I don't use PCs), or don't have a demand I do.
When I was last in Australia, I think I ended up doing a mobile solution from Optus, but I had to be really careful about how I used it.