I needed five gallons of an off-white paint for the inside of my garage. Did not want to spend the $30 to $45 per gallon. I checked with the paint store staff for contractor/customer returns and they had a five gallon bucket of a tint close enough to use in the garage. Saved a lot of money because they wanted to get rid of it.
I will consider doing the same if I just need a gallon of paint...