Sweet Valley is a brand of inexpensive soda.
The Sweet Valley brand name is held (and the sodas are produced by) Aldi, Inc. (Aldi is one of the cheapest chains of supermarkets around, they have stores mostly in the midwestern United States, and are based out of Batavia, IL).
Sweet Valley's selection of sodas include a Cola, Diet Cola, Lemon Lime, Orange, Grape, and a Dr. Pepper imitation (Dr. Thunder I believe it is called). These are the only flavors available at my local Aldi store, which leads me to believe they are the only flavors made by the company (since the store owns the soda maker).
The sodas themselves taste fine by most standards, although the Diet Cola (my poison of choice), has a distinctively "metallic" taste to it. This particular brand is the cheapest available in my area (even cheaper than Vess), costing about half the price of Coke or Pepsi.