We have used minivans and SUV's for our 3. First time we took all 3 kids, we took our car seats from home. Stupid idea considering the amount of luggage we ended up with, plus a 9 month old that needed carrying.
Last year we hired car seats. We used Alamo and Dollar. Alamo seats were cleaner and in much better condition than Dollar.
Minivans, we have had the Dodge Caravan, and Town and Country. Both had anchor points on the two captains chairs in the middle row, and another on the back row. Loved it. Kids could not touch each other, and we could not hear the child in the back row. I want one!!
Last year our kids were 6, 5 and 2. The 6 year old (who was 2 months off 7) used one of those base only seats, 5 year old in a full booster and 2 year old in a car seat. We easily fitted all 3 across the back of a larger SUV. If you want to know what types (we had 2 different cars), let me know and I will find out.