Making a cellphone is easy. You go into a mine, pull up some ore, extract various metals and then add components that you manufacture from other mines. Then you have to get FCC clearance and create lithium ion battery. Finally, you need to write a Snake game. If you can’t do that, try RePhone.
The project is actually a tiny circuit board with a SIM slot and an optional screen. It also supports Bluetooth. You’re going to want to get the $49 Kit Create, a tiny watch-like system that includes a little case and all the modules. It’s like getting a tiny unlocked cellphone for under $50.
It’s a fun little project and it works pretty well. While you won’t gain the experience of mining your own gold for wire traces and learning chip fabrication, this will let you make a phone quickly and easily which is great for all of us hobbyists without ready access to mineral rights.