Google voice is a free phone number ;) I have a couple for 2fa if i ever truly want it. The danger of 2FA is that you are trusting your phone service provider. A semi-common hack is to socially engineer a phone provider into transferring the target's phone number from their service to your service provider under a false or stolen identity. Now you can control the phone number, tie it to your own device, and recieve the 2fa sms at your own device.