But not as bizarre as the fact that you think people should work for free...
You can (or use to), encounter such a concept, at least in the UK.
Consider a hairdresser.
There is the standard charge, for simplicity, lets call it £10(-) .. £15(+) for a haircut, by a standard, experienced/qualified hairdressing professional.
The same hairdresser, my occasionally offer reduced prices (or even free), I can't remember exactly, by I think it was something like half-price, or reduced price, as a minimum.
If you let the trainee hairdressers, cut your hair.
So, a similar concept,
could apply, to an upcoming, not yet properly experienced/(qualified if/as necessary)/equipped/etc, repair individual/shop/entity.
I suspect the right/better way to do it, is for the repair person/company, to offer such a service (free, unless we succeed in repairing your device), on a case by case basis.
I.e. Only with certain types of repair, and certain (trustworthy/suitable) customers, with perhaps other stipulations.
E.g. Some faults, by their description, can sound like the repairer, has a reasonable or better idea, as to what is wrong. So, success is likely, and finding out it is unrepairable/uneconomic etc, would be reasonably quick.
If it was a PC, an estimation of the parts and repair time, is not too difficult. So for a competent PC repair technician, accepting a free, unless we fix it. Wouldn't sound too bad.
But other electronics repair, especially to the individual electronic component level, can be problematic/expensive/risky, as already mentioned by many others, in this thread.
But if it is building up, an upcoming repairer's, experience level. Without them needing to pay (possibly lots of money), paying for learning resources (such as actual qualifications). With perhaps significant upfront costs, no guarantee of final success.
Possibly needing financial resources, that the person involved, simply doesn't have access to, at the moment (i.e. a sort of chicken and egg situation).
Then maybe, it could be a solution.