for my terex 4792 It costs me around $10,000 a year for insurance,it's based on gross income though so yours could be more or less.On average it costs me 10k-12k per year for maintenance of the boom and the truck it's mounted on,although that could be less if you don't use your crane as much.Mine goes out everyday,averages 1500 p.t.o. hours per year.Cranes are very expensive,in my opinion if your not needing a crane all the time then just find a good crane rental company and be happy with that.You might think 100+ dollars per hour is a lot but trust me,you'll come out ahead at the end of the year.Not to mention the cost of an operator's salary.Just remember this,if the boom has to be taken apart to re seal the cylinder or change wear pads or whatever else,it's gonna cost you 10k so make sure you have a stack of Benjamin's handy.