Pat, I'll attempt an limited explaination of why we have to markup, but hopefully someone will expand on it.
When I got started and was working by myself I used to never markup my materials. I had about $2000 in inventory on the truck alone. Some items sitting there for years before they got used. If I had that money invested in the stock market I could count on 8% per year. If you don't markup, you lose that at the least. Second, it takes time to purchase materials, stock them, inventory them, etc. Nobody pays you for that time. What if a part is bad or your helper fries a $50 1000watt dimmer while installing it. Is the customer going to pay your time while you drive to the supply house and either exchange it or have to purchase another out of your own pocket? I doubt it.
We actually buy many items so much cheaper than home centers sell them for, that our mark up makes our price only slightly higher, so we don't get many complaints.
