Vehicles that are inexpensive to insure typically as those that statistically have been involved in a lower amount of crashes. That can be contributed to the driver of the vehicle as well.
We all think of Mini Vans being popular with families and parents typically drive a lot more conservatively with children on board. Thus they tend to be one of the most inexpensive vehicles to insure. Sedans are also less costly to insure than 2 door vehicles. Which, again, can be because younger drivers like the sporty look of a two door and are involved in more accidents than older drivers.
The average repair cost does impact the cost of insurance more heavily than the price of the vehicle. Check with your agent on the cost differences between models you are considering.