help

[Briggs Man]

I would like to know what i should be charging to cut a lawn which is roughly 30'ft by 150'ft i cut the lawn abput 3 times per month,also is getting insurance a good idea what are the costs and coverages of insurance ,liability i suppose,as at the moment i im just doing this as a side job but i would feel good knowing i'm covered incase a rock comes flying from my mower into someones eye.