I'm getting my foot in the door with a gas station chain and they're about to make me a preferred lender for their company. I'm in the process of making an ad for their monthly catalog they send out for their stores. I need to figure out some set prices to clean the whole parking lots including the gas pumps and side walks. Store fronts and canopies will be separate. I will be cleaning with a surface cleaner, using chemicals for stains, and removing gum around the islands and sidewalks. Some stores will obv be more dirty, bigger, or further away than others. I will need 3 different prices for the 1) parking lot, gas pumps, & sidewalks, 2) canopies, 3) store fronts. Should I just come up with a flat rate for these services or price them based on each job?? How much should I charge???