> Cost was 330 USD for PCB manufacturing and assembly of two PCBs and additional 225 EUR (240 USD) for components from Digikey that I soldered myself. This is including 24% VAT and shipping costs.
I actually didn't use any expensive test equipment, only oscilloscope and multimeter. Even design and simulation software was all open source.
Expensive signal analyzer or spectrum analyzer would have been useful, but they aren't absolutely necessary. It's possible to use the radar itself for many tests and debugging.
I have tried to limit the projects I do on my own to only the equipment that I have home and open source software.