It's been almost 5 years since I had my shop, Garage Keepers liability at a fairly high coverage amount (we would have 25 + cars on site at any time) ran around $8k/yr through Ohio Casualty. I forget exactly the deductible, but I'm thinking it was around $1k. This was for a "typical" garage policy. I was visiting the guy who painted my Dodge the other day and somehow shop insurance premiums came up. He says he pays a little more than double what a "normal" body shop would because he's classified as a restoration/hot rod shop. Said there were only two providers for here in Nevada. Perhaps that's the situation you're in, ask your agent. As for the waiver deal, I'm no attorney, and I don't know of any that hang here, and that's the only place to go to get a realistic answer. My guess would be you would be leaving yourself wide open for a law suit, regardless of a signed waiver from the customer. Courts aren't very sympathetic to a "knowledgable" business person "taking advantage" and being "negligent" to a poor, inexperienced, unsophisticated, blah, blah, consumer.