The excavation calculators include various calculators that help estimate the cost and help plan your job.
It is pretty hard to come up with an upfront price for the cost of excavating. The amount of time it takes to excavate a hole for a basement will have a lot to do with the operator's skills, and of course, the great unknown of what is in the ground of the excavation location.
Most likely, the excavator will charge an hourly rate.