R44 operating cost
I was doing the math recently.... you can use the pdf file about direct operating cost from the Robinson website as a guideline but you should adjust the numbers for fuel, mechanic cost with the cost from your area.
Also consider that the reserve for overhaul... you need to include cost for shipping of those items to where ever you intend to get that service.
Do you have a Robinson mechanic in your area? Include travel cost if not...
Insurance can vary quite a bit as well depending on the pilots experience.
It's a great helicopter for the money you are spending!