Dear Ramesh,
The value you entered in product master either is cost of the product used for valuation of the product in the company.
The value in the purchase order is the price of the product with which you would purchase the item from your supplier.
To automatically get a price in your purchase order you have to maintain either of the following
1. Contract under Sourcing and Contracting Work center
2. List Prices under Product Portfolio work center.
Note :
1. Only contracts or list prices that have been set to Active for Sourcing will be considered.
2. A contract always has a higher priority than a list price, unless the list price was set as a fixed source of supply
Related Help document :
Sourcing Rank in Assign Source of Supply
Source Determination
Regards
Leo