The answer will greatly depend on your area you are operating in and your equipment. You might get $50 an acre in Dallas, but you would struggle to get that where I live.
You should figure out what it costs you to operate your equipment, tractor, bush hog, truck, trailer, insurance, fuel, etc... and then add on what you want to make for yourself. Then check if you are competitive for your area. This is how I do it atleast. This way I can really narrow down costs and become really competitive with the other guys.