The only way to know what is cheapest for YOU is to do the legwork of contacting all the various companies insurance companies for a quote. I do this every few years, though at this point my insurance is so low that I doubt any company is ever going to be much if any cheaper.
For disclosure - 43yo single male, clean driving record except for one minor at-fault accident two years ago. In Westbrook, Maine. Homeowner's insurance with same company. 500K\100K\300K Liability coverage, $500 deductible collision, $100 deductible comprehensive runs me $55/mo for my BMW, and $49/mo for my '02 Jeep Grand Cherokee from State Farm. That minor accident is dinging me for $13 every 6 months per car, it is good to be oldish.
The Jeep was actually slightly MORE to insure than the BMW until I had them change the usage to less than 7500 miles a year.
Insurance companies can be pretty odd sometimes - I had great prices from GIECO for many years until I bought a brand-new VW Golf TDi (90hp diesel!) back in '01. GEICO quoted $1600/yr for that car, State Farm wanted $750. Been with them ever since.