Tomorrow, I am bidding to AERATE A TWO ACRE RESIDENTIAL lot. I've never done anything that large before, and don't know what to charge. I will be using a Bluebird 48" pulled behind a large lawn tractor. I believe it is a fairly OPEN area, but will also have my walk-behind for any tight spots. My guess is that it will take me 1 1/2 to 2 hours. What should I charge? Is there a "price per acre formula" that I could use? Thanks for your input!