For some years I have been trying to make an aircraft for less than $10k. First attempt was scrapped as it was far too heavy. The idea was to make moulds and loan them out, really not feasible, too easy to damage the moulds. I am on second attempt now. Engines $4k, leaves $6k for fuselage etc. Use phone efis, may work. Hand held radio. Probably on target but making many parts in my lathe and milling machine. I expect that I will achieve the end result. The aircraft is small and I am using quad bike braking system. I machined wheels from single blocks of aluminium. Canopy will blowv$10 if it is bought, I will have to make it, doubt that the result will be ok.
I have many 3d printed parts. I have spent $4k on tools, excluding lathe.
I am 74 now, I don't think that I will finish it before I loose my medical.