When you want to implement a low cost IOT solution with bluetooth interface, you can consider using a ESP32 development board. In addition to the bluetooth interface, the ESP32 development board also includes a WiFi interface.
In order to run a program on the ESP32 Development Board, we will need to write our program into the flash memory of the development board. Since it is easy to write code and flash programs with Arduino IDE, it is a good tool to use with the ESP32 Development Board.
In case you need it, this post shows how to enable ESP32 development on Arduino IDE.