Dubbed anime is often despised by hardcore anime fans because usually the voice acting isn't done as well as the original japanese voice acting. Any real anime fan will tell you to buy the subtitled anime because it sounds better, and produces a more dramatic effect in the end. Sometimes a good dub comes along, and that is why DVD and anime work well together.
Dubbed anime costs more to produce that subtitled anime. However there is a larger market for subtitled anime, and the studios know this so they make the subtitiling more expensive in order to cover the costs of the dubbing process.