Have an Exit Strategy. A master supply agreement is a legal contract between two parties that consolidates two or more current contracts into one streamlined agreement.Edit, sign, and share master supply agreement template online. No need to install software, just go to DocHub, and sign up instantly and for free. Details about additional contracting processes such as Real Property Transactions, Contract Modifications, Purchase Orders, and Task Orders. A master purchase agreement is a legally binding contract between buyer and seller, and typically relates to buying and selling goods rather than services.