I’m looking into getting a flip phone with a separate number so that I can sign up for a few apps that without associating them with the complete identity profile in the data marketplace that is linked to my actual phone number.

To be clear, the apps will still be downloaded and utilized on my primary smartphone. But the phone number through which I receive verification codes during registration will be a separate device.

Has any one done this? Tips for selecting a cheapo phone and prepaid service?