Ordering activities shall establish the BPA with the schedule contractor(s) that can provide the supply or service that represents the best value. A blanket purchase order is a convenient way for businesses to cut down invoice processing time and costs for their vendor relationships.One such critical document is the California Residential Purchase Agreement (RPA), the primary contract used in residential property sales in California. • Type of purchase order or contract identified, e.g. Pricing and other market-sensitive data within this Contract may be exempt from disclosure under the California Public Records Act and.