CRG
Helicopters are expensive to operate - capital costs, depreciation, fixed and variable maintenance, repairs, insurance, taxes/licensing, hangarage, fuel..... That's why the hourly rental costs are so high.
But, there is a point where ownership becomes viable and for private owners, this can start from about 100hrs pa upwards - especially when you include the benefits of knowing it's your helicopter, maintained to your standards, available when and where you want it.
Obviously lots of people would like to own a helicopter and make money out of it, but few do. Those that make money from helicopters normally work hard and shrewd.
Not a fan of the Robinsons, but their costs are likely to be the most predicatable, aided by the economies of scale. They were designed and built to satisfy the budget end of the market. But, more importantly, you would need to make sure they are the best helicopter for your intended use.