I have an Ultra Mobile eSIM as a second line on my iPhone. Costs $3/mo and you can buy cards to top it up or add a credit card. My primary eSIM is a regular phone plan.

It works surprisingly well. I can easily turn off the second line in Settings without removing it.

I could’ve bought an unlocked phone with cash somewhere and used the SIM in that. They wouldn’t know who I was.

I didn’t do that because it was inconvenient and it wouldn’t be anonymous once I started using it for SMS authentication.

Wait, how did you get it so cheap?