[Solumina]

Go to a beauty supply store, most likely there is one in your area that is open to the public (Sally Beauty Supply is the only nationwide chain that I can think of off the top of my head), they will have the best prices, besides direct from the manufacturer, and they will have a much wider selection then pretty much anywhere. Most of them also have knowledgeable staff who can help pick out the type that will work best for you, know how the products will interact with past hair treatments, how the color really shows up, and how likely it is to fade.