A master purchase agreement is a legally binding contract between buyer and seller, and typically relates to buying and selling goods rather than services. This Master Contract defines and provides for coverage and administration for the benefits common to uniform CITY employees.This Amendment and Restatement of the Master Interlocal Agreement Between City of. Please Fill out a Survey. An MSA allows for some variability in the specific details of each project via the SOW. The demand for downtown living in the City of San Antonio. San Antonio, TX, 78238, 1,800,000, 1,800,000, 58. Unless otherwise stated specifically in a Purchase Order, this Agreement shall apply to any and all transactions between Buyer and Company. 1. Definitions.