I guess your local Robinson dealer can best answer your questions, based on what you are going to do with your machine.
What comes to mind (other than the purchase cost) is:
- fuel/oil
- insurance
- maintenance
- airport fee
- hangar fee
- maps and gps updates etc
- fees to get and keep your pilots license
- fees for doing commercial flights
- white shirt with stripes ;-)
- profit taxes
I also guess that there are at least one or two other threads about this topic
