Most of us already have free SD cards laying around, and reading the fine article’s scenario the phone which the author already owns and carries around also doubles as the screen, so no need to buy a second phone. So I read it as costing around $20 for the base setup described.
And you don’t need to trust a sketchy flavor of a phone OS or other sketchy phone subsystems made by vendors who do not have tight controls. Unlike Pi, phones are a highly targeted device type by certain governments including governments of countries where phones are made.
And you don’t need to trust a sketchy flavor of a phone OS or other sketchy phone subsystems made by vendors who do not have tight controls. Unlike Pi, phones are a highly targeted device type by certain governments including governments of countries where phones are made.