Id go ask 3 different local companies atleast for bids.

I work for a big out fit. We stay covered up in dirt work. All the small companies look very busy as well. We are developing like we were before 2008. So its a bad time to get a cheap estimate id say. Im not an estimator so id be afraid to give a rough quote but i been doing this for about 15yrs. The correct and safe way to do this is to hire a company that will use a dirt testing company. That will ensure you that you have the correct compaction, correct lift thickness and the correct dirt to be used. You do not want it leaking 10yrs later or settling.

You do not want to spend your cash on some half azz work that "looks" good. Whatever you do, make dang sure you hire a soil testing man. He will make sure the operators do everything correctly. Like putting the dirt down in 1ft lifts then compacting it with a sheeps foot roller then him testing it for confirmation on targetted compaction and moisture levels. If its not packed enough, they have to fix it til it passes. The soil company is liable if it fails later on. So they usually make sure. But you need to watch them like a hawk cause its usually a $12hr employee thats in college that doesnt want to be there.

I might be over board but if its 100 yards long and 15ft deep, thats serious. The testing company only charges $100 for each test. So its worth it considering the risk.

You can factor that equipment rates on the cheap end are $100 an hr with an operator. So $100 an hour for each piece of equipment. If the dirt is already stripped of top soil thats good. A real company will send a soil tester to your fill dirt for it to be tested. A proctor they call it. It tells the moisture level, how well the dirt will pack. I have seen good looking dirt fail these proctors. I would want a proctor.