I recently found a cheap and interesting HAT (15$) for the rpi 0 on aliexpress, it was a cheap lcd screen and buttons that used all the gpio pins to power it and its about the size of the pi itself. its designed to be used with retropie and I could see it being a cheap way to make a portable raspberry pi retro system. The only thing missing is a case and a battery but I can modify an existing case that uses screws to fit it. I saw a lot of batteries packs that would work but they all were expensive. is there a cheap and portable way to power the pi? it needs to be about $10 but it can be lower or higher. at this point, I don't care if its powered externally by usb.