Around here, Well Drillers charge by the foot, usually with one price for cased (with a steel, welded-together pipe casing driven around the hole - necessary for going through dirt, sand, and softer rock) and another for uncased (OK after they get down to hard rock and still haven't found a good vein of water yet). One of the larger local outfits is infamous for overcharging by lying about the depth of the well. I have several neighbors in the subdivision next door who were all charged for about 300 feet of cased hole and 300 feet of wire and pipe going down to their pump, but who only had about 150 feet of pipe and wire to be pulled out when they had work done on their wells due to problems later on (I kinda figure the holes are only 150 feet, too). The same infamous outfit did all their wells. So it might pay you to check with older customers who could maybe verify the accuracy at which different Drillers measure depth.