Setup for Auto-PO when generating from MRP action List
 
Last Purchase Price for a Supplier The last Purchased Price for the Supplier Selected in the Preferred Supplier field 
Quote Price Price from an Approved Quote in the Quotation & Estimating Module.
Standard Material Price Standard Material Price listed in the Inventory Control Module.
Last Purchase Price Last Purchased Price.
Contract Price Price listed in the Contract Pricing Module.
Target Price Target Price listed in the Inventory Control  Module.
Manual Entry Enter Price Manually