It's useful for an artist to understand some of what's going on. Art doesn't necessarily follow the standards of supply and demand. Keep in mind that a high price may be part of the mystique in selling difficult art. Add to this the excitement some dealers get from making high priced sales. Unlike a new Chevrolet, art is a perfect commodity for profiteering because no original piece is exactly like another.
Value is in the eye of the beholder.
Furthermore, a sale to one party at a certain price facilitates sale to another at a similar price. Keep your price list simple and stick to standard sizes. Do not vary the price on works just because they have more or less effort in them. If your work is selling readily in a given price range you have the opportunity to test the upper side. The price of art can go up, but it ought not be seen to go down.