I did it too. But, what the hell is this question supposed to mean:
Automobile tune ups and repairs are quite costly. Did you know that in Canada, service locations typically bill significantly more for labour than for actual auto parts?
Apples and oranges, you can't compare labour and parts costs. Or, do you mean that for a typical "tune up", labour makes up more of the bill than parts do? You should say that.
Also - since the advent of electronic ignition and fuel injection and computer controlled everything, the notion of a "tune up" is pretty much dead I think.