Optus seems to have increased the wholesale cost of 4G mobile data.
My current $70 per month 200GB plan with Optus is expiring.
This is the cheapest one now for 250GB of 4G data via the Optus network. It is also unshaped (unlike others which limit you to 12/1). I get 40/20 usually.
Viable NBN replacement for some, especially if you are still waiting for a connection, having issues with HFC or prefer the mobility of a 4G connection.
Optus is currently offering 500GB for $68 a month with no contract. I was able to get the offer without the included modem (and associated cost) via chat last night. Apparently the service can be a little picky about the modem you use though.
https://www.ozbargain.com.au/node/506169