In the US or the EU the typical "cost" of a CNC machine, internal burdened cost, aka all costs factored in, tends to run around 40€ / hr.
This means that if one runs a machine at 41$/hr one makes about 1$ gross contribution margin, incremental.
The cost includes the burdened avg. cost of an average minimum level operator,
shop floor cost (rental, heat/air/permits/taxes/whatever, overhead in bookkeeping and billing),
breakage, maintenance, tooling, setup,
ancillary tooling like parts cleaning,
wash, polish, tumbler, debur, metrology, packaging, shipping, etc.
Cost of material stock, racking, handling, stackers etc.
The incremental marginal cost may be much lower, sometimes, but it is a false premise that Your work and situation will permit that in any significant degree.
This means You can potentially, in theory, run a night-time shift, yourself, at 5$/hr "machinery+power" costs, after lights-out, while paying yourself no salary and or benefits, from the work You do.
False:
IF You could do all the work Yourself You would need no staff, bookkeepers, cleaners, maintenance etc. and still keep working 2 shifts producing parts 16 hours per day.
AND simultaneously selling, marketing and keeping up with clients.
In reality, You need to figure the costs of an experienced-skilled independent operator into the mix for night-time aka second shift, plus parts wear & tear.
+ CNC, tooling, ancillaries, etc.
Tends to run near the 40$ / hr figure, often higher.
A really skilled CNC operator night-time, will get 25$++ per hour.
If they don´t, they walk, sooner or later.
If they are not really-skilled they will make parts with errors or errors-with-machines, You will then wish You had paid the extra hourly salary for.
Reality check.
A really good automated system can drive the cost down to 5-10$ / hr.
Flextronics is a good example.
500k workers, 20.000+ robodrills, 51 ops for an iphone for 8$ total billed.
Maybe 30 minutes processing time for 51 ops.
16$ / hr with 15% margin.
With (nearly) free land, free loans, 1B$ / plant to set up, no hazmat fees, no taxes, no permits, no real accounts/taxes costs.
600$ / month workers.
Free shipping, nearly.
YOU are NOT flextronics, and You most likely cannot get endless workers for 600$ / month.