Normally this is not something I would have any interest in writing about but as you all may know, I am currently unemployed. This certainly makes you aware (worry) of possible auto repair costs.
My hubs is relatively handy (he's not Mr. Goodwrench) but very short on time, he puts in a crazy number of hours at work each week. He is also very frugal so he always tries to do auto repairs himself, if possible. I used to argue that taking the cars to our mechanic was more sensible since it always seems to take about 5 times longer than his estimated time of completion by the time he goes to buy the parts (then return the wrong ones).
He recently discovered a website that makes this process just that much easier and worthwhile, carpartswarehouse.com. The site is very user friendly and if you have any questions there is a toll free support line to smooth the way. Oh, they also offer FREE SHIPPING on any orders over $50.
Ok, very easy, real live support, big cost and time savings. No downside that I can see.