What did you charge as an excavation contractor? That would be a good start.
It's hard for us to come up with a number for you, well, it's easy, but it's hard for it to be accurate
Since your from Utah, I'm going to assume your soil is pretty sandy, and easy to grade. I don't get bother to put my tractor on the trailer if I'm not going to make at least $400, and that wouldn't be a full day's work either. I try to average around $100 per hour, but I typically charge by the job (which some are against) and wind up ahead. On my last job, if I charged by the hour, I would have only made $1k dollars. Since I charged by the job, I made 2500, and I there were two higher bids than me.
Don't underbid jobs. Don't undercut your competition. Provide a good service, don't leave until the customer is happy, and be sure to spell out the charges in advance, so there are no surprises.
To me, it's more important to make the customer happy, than it is to get a few good paying jobs. Almost all my jobs are from word of mouth, people being happy with my service, that's most important above all.