I work in parts and this is how is look at it. I would rather sell a part at 10% over cost than not sell the part at all. However it does get annoying with everyone and their mother asking for discounts. If you ask me to price match that is fine, I do tend to get a little upset when people just come in off the street and say "Is that the best you can do?" No its not the best I can do, I could give it to you at cost, but how the hell am I suppose to make any money.
sorry /rant