Invoice before payment

[mscentex]

I have two buyers trying to buy more than one item.  One is requesting an invoice before payment.  His items are in his cart, but he hasn't paid.  They are listed as buy it now.   Comments indicated I can send an invoive, but only from orders.   When does the item become an order?  Does he have to pay first?   Then would I have to refund shipping?

Another has 4 items in the cart, but is showing shipping for each item.  Does ebay refigure the shipping automatically?  At what point am I able to adjust the shipping costs?

Thanks

[lady_madonna]

@mscentex 

If the items are in their cart, they can click on the button "Request total from seller".