Price is determined by a myriad of factors - each factor has its own pull. Although this list is not exhaustive, here are some of the factors to get you started. Grape quality . When a vine yields lots of grapes, the flavor in the grapes tend to be less concentrated, thus the wine tends to be less flavorful. Jug wines, which are plenty, are made from vines that produce plenty of grapes.
More expensive wines come from vines that produce small amounts of grapes.
A sunny, warm summer generally means well-matured grapes. A wet and cool summer will stifle maturation. Wines made from immature grapes will be of a lesser quality, and generally less expensive. The weather at harvest is important as well - a deluge of rain at peak maturity will water down grapes. Some wineries limit release just to take advantage of this phenomenon.