If a wall is white and you want it red do you paint it with a dark primer first?

Any, but usually you use the same brand primer that your paint is.

Most places will tint your primer the same color as your paint if you ask, this way you don't get shading.

Lowes brand paint, is one of the best tested paints, for around 34.00 indoor and

39.00 outdoor, it is rated better then Behr paint from homedepot.

The best outdoor paint runs around 50-60 a gallon.