As was mentioned earlier, you have to start with smaller jobs that you feel certain you can complete with in a few hours or by the end of a long day. You have to try out your equipment and have a feel for the most media and fuel you can use. I know I can go through as much as four bags an hour when I am going full out, worst case. I know my compressor will burn about two gallons an hour. at around nine bucks a bag that's forty and throw in eight for diesel. If I would like to earn one hundred an hour I can charge $150. per and be there or better.
Alternatively you can say to your self, after looking at the work ahead, I would be happy if I came out with $500. for the day. You might offer to do the work for five hundred plus material at x amount per bag and let the customer count the bags with you. You can offer a little higher price per bag if you want on going labor. You could just say $15. per bag. They don't have to know what you pay for it. Or you could say $500. plus forty an hour, or whatever cost you figure per bag you might use in one hour. I like the set price plus cost per bag. If you work hourly you may have a customer watching the clock and asking if you are charging them every time you stop for a repair or to rest or whatever. By the bag means they can not argue with you and the set price means you will not go home empty handed. You can't loose with this method and you will get better at knowing what you can get away with over time which will depend on the customer and the job. You always set the big price first. If they talk you down from $700. to $500. it's cool because that's when you tell them okay plus media at $25 per bag, or whatever will make up for the two hundred. If they take your first offer you can be a sport and give them nine bucks a bag. Any questions?