Well, it's not as bad as one would think - -
205 $ US per year for liability personal injury and property damage for a standard single engine plane. https://avemco.com/aircraft-renters-...ote-rates.aspx
Adding in automotive insurance example, a Mercedes S65 AMG (convertible) is $3,835 per year average..
So 4000-4200$ (US) per year may be a realistic assumption..