The valuation in SAP can be at the plant level or the company code level. If you define valuation at the plant level then you can have different prices for the same material in the various plants. If you keep it at the
company code level you can have only price across all plants.
Valuation also involves the Price Control .Each material is assigned to a material type in Materials Management and every material is valuated either in Moving Average Price or Standard Price in SAP. These are the two types of price control available.