Today, with the availability of electronics, tools, and 3D printing (or popsicle sticks), you can easily build your own FPV micro-drone for about $50. This is demonstrated by YouTuber his Max Imagination. It also requires a lot of tenacity. Max's little quadcopter uses an Arduino Pro Mini and his MPU6050 as his controller for flight and receives his RC signal through an nRF24L01 radio module.
This small aircraft has a control range of about 50 meters and can fly for several minutes with a camera attached. Price listed is $45, plus or minus $10. This depends on what is available and the type of delivery of parts required.
Besides the electronics, perhaps the most interesting feature of this drone is that the frame can be constructed from popsicle sticks (and a wooden match or two). Max provides his template for cutting drone frames along with other information in the video description. So, in theory, it could also be assembled this way. Alternatively, you can purchase the print file if you prefer.
It's an interesting build, but if you just want to fly a drone, you're probably better off just buying one. Starting around the 12:10 mark, there was a fair amount of troubleshooting involved, including adding an EMF shield and replacing the motor. Max built a transmitter based on: Video by Emilostuff, This definitely increased the turnaround time. Still, if you can fly something like this after all the trouble, you'll definitely be satisfied.