In the fall of 2010 I paid a flat fee of $750.00 for someone to clear off about (8) years of growth from about 6 acres. He thought it would take him (2) days and he spent (4) days on it, and he got about 4 to 4.5 acres of it done.
He was just starting out in the brush hogging business, he said. In fact, he looked at the property by himself on Friday, I meet him at the property and made a deal on Saturday. On Sunday he went and picked up a brand new Mahindra 4530 with FEL & Rotary cutter, and started in on it on Monday Morning.
I have not seen or heard from him since, but I would think that he never again "firm priced" anything other than the simplest of jobs. I think he learned a bunch about the brush clearing business on that first job.
I know that I did.
EDITED TO ADD: Just prior to hiring the brush hog man, I had a quote from a brush clearing outfit (with skid steer-mounted mulchers). Not a firm price, but they estimated about $3,000.00
I also had a quote from a bulldozer guy; Run over everything with a D5, bury rocks (lots of rocks), burn stumps, drag a harrow of some sort over the whole place and seed with fescue; $5,000.00 firm price.
EDITED A SECOND TIME: And, just for fun, there were the very first guys I hired to deal with this property. 2 'good ole country boys with a beat-up tractor & an equally beat up rotary cutter. They said they could do the job in a day for $250.00
I told them to "have at it." They went a tearing out through the brush for about 30 minutes before they hit this big rock and broke their cutter. Loaded up and left and I never heard from them again.