$20 will get you a 32-bit processor (ESP32), with Wi-Fi and Bluetooth 5.0 built in and a 2.8" color TFT screen, programmable with the Arduino IDE. $3 will get

$20 will get you a 32-bit processor (ESP32), with Wi-Fi and Bluetooth 5.0 built in and a 2.8" color TFT screen, programmable with the Arduino IDE. $3 will get you a basic Arduino Nano clone.