Sample order posting Block

Dear Mates,

My requirement is there are two order types one is normal sale order which will be processed as regular.One more order type is Samp,le order which will be given free sample to the customer.In this scenerio i need need value should not posted to accounts.Can it be controlled via pricing procedure by giving only VPRS conditio type or can it be done through Sale sdoc type.Kindly advise