There is none. As with almost any product, you usually get what you pay for. Purchasing paint strictly on the basis of price will end up costing you more in the long run. Here's why. As long as you're comparing two similar types of paint (i.e. interior wall paint, exterior trim paint), price differences usually reflect a difference in the quality and/or the amount of the key ingredients. Since it's the ingredients that affect such important qualities as durability, flow, hide and leveling, the better the quality of the paint the easier it will be to apply and the longer it will normally last. In fact, a top-quality paint (or primer, or caulk) can last up to twice as long as a low-end paint, lowering the cost per year of service. Materials are a relatively small part of the overall cost of a paint job. Saving a few hundred on materials simply doesn't pay.