That is the problem with small lot + slow production time.
If it takes an hour for a 3d printer to make that gear.. thats something like:
1) Setup, calibrate, & Program machine - 15min? (labor$ + Priming material waste$)
2) Electricity cost ?
3) Material Cost ?
4) Take part(s) out, file/de-burr, sand, inspect / test.. (Labor$)
5) Reject & Remake or Box up and ship out. (Failure expenses$, shipping materials expenses$, labor$)
6) Paperwork & Website work. Order tracking. Taxes, forms, emails, printouts, ...etc. (Labor$)
Id guess he couldnt sell them for less than $20 using his current method, and you add shipping to that, and your looking at +$25 for a gear thats of low quality & questionable durability.
This is why I say, its value is of a $5.00 part, "to me". Its not that he can actually sell than for $5.
If you feel comfortable paying that much, for that level of quality, and for an uncertainly of its longevity... feel free to ignore the quips, and get them while they are hot off the glorified glue gun.