Combined shipping on multiple fixed price items.

[exit55]

Am selling some different items at fixed price.  Have multiple of item.  Listing as one but can take as many available.  Am asking buyer to wait until I invoice them before paying because ebay's shipping cost is usually wrong for a combined shipping cost.  Ebay will not complete buy until buyer "confirms and Pays".  Have deleted "pay immediate" from listing. What do I need to do so buyer can buy item and wait until I invoice them.

[reallynicestamps]

The buyer should be putting their purchases into the shopping cart.

However, I have also had the customer tell me in Messages what they want  and then made a special listing for them, using their name as the title (because no one will Search for that) .  This is usually simpler for the buyer for some reason.

[exit55]

Tried Add to cart.  It basically takes you back to confirm and pay button.  Right back to same place.