when I worked for a company, they used to take the cost of material and double that for the entire job (edging, weeding, raking, setting grade, laying, etc.). When I started up myself I didn't feel that i was getting compensated enough to cover my overhead so i upped it to cost of material times 3. this covered my time to go to the yard, get loaded, drive back and lay it as well as prep work for the bed.