Hi,
You have following options and chose best option.
Option-1:
As you are creating purchase order and check your MM pricing procedure find condition type used for material.Now use in t.code:M/06 and keep Condition category T (Moving cost) for that condition type and save.Now create purchase order, price will picks from MAP price of material master.
Option-2:
Refer and go for adopting PO price from PR
http://scn.sap.com/thread/3170319
and set tolerance limit for purchase order tolerance keys PE and SE your company code in following path:
SPRO -> MM -> Purchasing -> Purchase order -> Set Tolerance Limits for Price Variance
Regards,
Biju K