PR Valuation Price From Maintained Material Price

Hi,

I have scenario and would like to implement in SAP.

1. I have material with moving average price.

2. I would to maintain its price as per market rate which will change after 6 months or a year.

3. I want to create the PR for these material and user only has to enter the material and qty the maintained

material price should come automatically in valuation price of PR.

Kindly give the solution for that or if any BADI or user exit required.

Regards