I am considering starting a home improvement business in Connecticut , I already know how to get a contractors license but I would like to know what the average cost of liability insurance and workers compensation insurance is and is it possible to make monthly payments. I have equipment but need to know if start up costs are affordable before applying for license.

Workers comp and liabiitly insurance is often underwritten and rates depend on past experience, past claims, years in the business and more.
There are companies that allow monthly payments but many do require annual payments.

I would visit a full line insurance agent. They can give you rates from several companies

Also many contractors hire all their workers as sub contractors and do not have to provide workers comp,

I would also consult with a good CPA and Attorney that handle construction. Even if you don't hire workers, you need to have good contracts with your sub contractors, they also will need to provide proof of insurance. Also try www.sba.gov they can give you some answers also. Good Luck!