What is the average cost of insurance for janitorial cleaning business for an individual that is a sole-proprietor with no employees?

What type of insurance, on your office, liability, if so what limits
Busienss auto insurance since any auto you use in your business has to be insured for business ( higher rates)

What really makes the difference is the amount of coverage you want. Are you looking for liability only or do you have certain tools/equipment that needs to be covered as well?