I use a good exterior flat latex and put "3" coats on the first time. I don't think a primer is necessary.
Depending on weather and other conditions I will one coat again in 3 to 5 years.
Some time you can pick up a gallon of good paint that someone had mixed and wasn't pleased With the color, the store cuts the price up to as much as 50%. Bee hives don't have to be white. Most of mine are "Bull Frog" green, Others are light gray.:)don2