
It's building jigs and fixtures to hold the part for each different machining operation that takes the majority of the time.
Then you have setup time for each machining operation, the actual machining process, cleaning and de-burring, assembly, testing, packaging, trips to the post office, etc.
Add on costs for electricity, materials (and shipping of), and tooling (cutters($30 and up), drills ($5) and taps ($8 and up)).
When it's put that way, 50 euro is starting to look not so bad eh?

And from whatever he manages to keep after costs, the government will invariably want "their" share of.
Truth be told, I bet he just likes the smell of hot cutting fluid.
