I've come to the conclusion that maybe some of the more affordable mobile phones there are free or a net gain, considering the discounts you get from signing up as a new account on some apps.
Every mobile app that has a promotion for new signups relies on you bringing over an unused mobile number.
Some of them probably see your device's MAC address or serial number, so changing telephone numbers without changing
Uber new join ride - $10, and another $10 referral bonus for my main Uber account that referred it.
Uber Eats - ditto, $10+$10.
Didi - same, $10+$10.
Doordash - same.
So that's $80 in savings. Maybe there are other services that offer this kind of thing.
Assume a $10 minimal cost of a first month prepaid mobile plan.
Basically, if you can find a low-end mobile phone in Auspost under $70 is free, or even a net gain.
It just needs to have an operating system capable of carrying the above apps, which I don't know if they are.
There are a few handsets at that price range, but I don't know if they're even useful.
Just thought I'd reach out and check if anyone does this and if it works.
Or you could go one further and for every $2 sim you make $68. Don't even need to purchase a phone. In my experience they don't track the mac address, just the phone number.
But tbh, not really a revelation of sorts.