How to add Transportation cost on PO's and that will also update the Item Cost

Summary

We need to add Shipment cost for items in PO and it's should also update the item cost as well in inventory.

Content

We have one PO with 5 items price 1000 for all and now we need to add shipment cost 300 on that. 

Is there any possibility to add this cost in PO and it's should apply also on item cost as well for amount.

For ( example PO is for IT related ) 

1- Laptop

2-Desptop

3-Keyboard

4- Mouse

5- Windows License

So how we can apply the transportation ( shipment cost ) on Hardware as it's included in PO( Purchase order)  as Shipment amount 300.