Phantom 3 looks pretty expensive. I just need a basic hardware drone (no packaging or end product). But the only requirement is good software support so that I

Phantom 3 looks pretty expensive. I just need a basic hardware drone (no packaging or end product). But the only requirement is good software support so that I can write applications on top of it. I checked ardupilot and seems that any basic drone that follows its specifications would be good to go. Also would be ok if there would be DIY kit for drone that can reduce the cost as my main focus is on application on top of drone.