Hot topic- Materials are marked up for all the reasons already listed- we all purchase quantities at advantageous times(low prices on emt, wire) for obvious reasons and hold stock, just like the retailers. The retailers also aren't sitting handily in the parking lot, like our vans; the retailers also won't return to repair under warranty,labor included. I will not compete with retailers or even supply houses, if it becomes an issue with a customer, we tell them either that we won't install materials we don't provide(except lamps), or we will not warranty their materials AT ALL.(they pay for all labor, travel, diagnostics) This shows them the value of our policy. I think the "how can I make a living at this" question gets easier as you develop faithful customers and more word-of-mouth referrals. Our experience is that when you come well recommended, the customer will respect your judgement.(Every satisfied customer will refer 4 people, every dissatisfied customer will refer 10) It took about 10 yrs to realize that I didn't always "win" when I competed for EVERY job that came by. But, to get back to markup, everyone knows that the retail market will sell items at below cost(loss leaders) to get you in the lines. Also using one large orange place as example, many manufacturers are building special low price/quality product lines specifically for this retailer. A large device manufacturer(starts with 'L') makes a particularly cr@ddy line of dimmers to compete pricewise. It took a while to identify these products as we came across them-item number was same with a letter added, but the performance was less than supply house identical line. And which would you use in your home- Homeline or QO?