Cheap paints have a higher percentage of solvents per volume, say a gallon. As a result there is less pigment and resins in the gallon of cheap paint than high quality paint which can have 50% more pigment and resins than the cheap stuff. What this means is that most of what you are applying with cheap paint is water or mineral spirits (solvents up to 70%) which evaporate and leave little pigment behind. This is why you have to re-coat and re-coat up to four times with low quality paint before enough pigment is left behind to cover the color underneath.
So learn from the pros who value their time as you should. Buy the best paint you can afford and avoid having to paint more than twice. Look for high quality manufacturers such as Benjamin Moore paint, Behr paint or Sherwin Williams paint and look on the side of the can for about 45% pigment and resins per volume.