In the first few years of business I found myself competing with those guys alot. I always find it amusing when I give someone a quote, and they respond with "oh, well my friend said he will do it for free at his house this weekend". So am I supposed to pay you to fix your car? Thats the only way I can beat free!!!
I can tell you that I do not want the customers that are using the mobile/backyard mechanics. I most likely will NEVER make enough profit off of ANY job they bring to me. That goes for their vehicles, and most of their referrals too. In the last year or so I have been able to "weed out" all of the price shopper type of customers that I used to have. I make much more profit and have alot better customer service experiences by only dealing with the right kind of customer. I take all of that time that I used to spend on making a couple of dollars from the discount oriented customer, and apply it to keeping the ones that see the value in what we do. That has been the most rewarding decision I have made up to this point in business.
It is very hard to turn away work when things are slow (and money is tight), but I still don't give in. I always try to build value in my pricing when explaining a repair. I mention my great warranty, my quality parts, and my trained staff. If they are not interested after that conversation then I send them down the road. I can tell you from experience that is a good thing most of the time! From my experience they were the ones that take up most of my time, give me the most headaches, and at the same time pay the least. That is just not the business I planned on owning when I started it.
It really all comes down to what type of business you want/need. You can't have it all, and either can your customers!
JP