I use a buck a yard for rough estimating on projects around my place, with my own equipement. Allot of times I can do it for half that, but sometimes it costs me more. A bigger machine can move dirt cheaper then a small one, but you need to move allot of dirt to justify the bigger equipment. It costs allot of money just getting equipment on site, then the monthly payments are a constant. Soil type can also play a big role in what it costs to move dirt, as does the working condistions. If I have open space, I can move allot more dirt then I can in a wooded area.
Eddie