deks commented on a Build, Cheapest Whoop Possible   Sep 23, 2017  

Currently it may be possible to pick up the BeeBrain v1.2 FC for cheap because NewBeeDrone is about to release a new version. I got one for $10 from RMRC (now gone from there, but other shops may still have them in clearance).

Also currently, you can get 6x15mm 17,000kv motors from AirBlade for $6: https://www.airbladeuav.com/collections/clearance/products/airblade-6x15mm-motor-for-inductrix-speed-insane-set-of-4-motors-2xcw-2xccw (use "Fall2017" coupon for 40% off).

I was able to pick up a RMRC CM275T cam+vtx AIO for $8 (was also on clearance, not available now).