As a non-aviation service provider (CPA) I sense that the IA/A&P has some of the same issues as CPAs: Lack of perception of value. Don’t forget the learning curve value that you aren’t paying for. And what about the research materials that you don’t have to buy? And tools, etc.? A good mechanic is worth more than the invoice you get from him/her.
My retort to that would be the best money spent is paying for the best lawyer…or CPA in town. I definitely agree on that and paying for the best mechanic in town in an aviation concern would be right there with it. Unfortunately I paid for the best mechanic in town on that one and unfortunately I didn’t get him 
Here is another, not the same mechanic story…
I visited a different mechanic to do a prebuy inspection for me he did it billed me and I paid him. He inquired if I wanted him to do any of the fixes of the problems that he found in the prebuy inspection or some of the upgrades I intended to do? So I said give me an estimate of what you think it will cost to fix them and do the upgrades. So he faxes me an estimate and then mails me a bill for research time when I told him I was not going to have him do the work. Needless to say I called and said you have got to be joking…I have never gotten a bill for “research” to bid on a job I think that is the point of the Bid!
This stuff floors me 
you can’t make this stuff up, it was a different mechanic at a different airport than the other guy. Unfortunately it is a tough business being an airplane mechanic and self employed unless you find a niche I guess. I respect that like a CPA, Insurance Agent or Attorney, been self employed for 20 years. I guess I am finished now, hope you enjoy my crazy mechanic stories.
I’ve done the owner-assist annual thing for 21 years. I learned a lot, saved a lot of cash. And most importantly, I discovered that my plane was in much better condition than the one the shop maintained. I am absolutely serious about that! However, I also found it harder and harder finding an IA who will work with those of us who want to go this route.
I finally have just made the sad but necessary decision. The plane is sold and I’ve hung up my wings. No more $135 ELT batteries, no more $50 spark plugs, no more $125 AirHawk tires that arrive seriously out of balance, no more $6/gallon fuel, no more BFRs with CFIs who don’t know a darn thing about protecting my engine from shock cooling, no more ADs that really make no sense, no more fighting with the Airport management, etc. etc.
Breaks my heart really, but absolutely the correct decision.