Came across this phone a week or so ago. Don't have one myself, but seems to review quite well.
Have been keeping an eye on the price as I would be interested in trying as an alternative to original pixel whilst waiting for a 2019 phone to inspire me.
This is the cheapest I've seen.
No details on site about being locked, but there is a comment about the 'beauty' of optus pre-paid plans and it is listed as a pre-paid mobile. That being said I would be trying to get OW to price match this. Not sure if they would get out of it because their version is unlocked…
Still I'm sure it wouldn't cost $98 to have optus unlock it..