Sellers set the combined rates, not eBay.
If you have NOT yet paid for the items, the seller can easily send you a combined invoice. Either go to your shopping cart and click the request to receive a combined invoice, add a not that you are ready to combine the shipping for your purchases. Wait for the seller to respond. you can also go to your Purchase History page. to the right of any of the items will be a link to request a total (be be in the "More Actions" tab). All items should appear in a total request and you can then click to request the total shipping invoice.
IF you have paid for the items, you can request a combined discount from the seller by sending a PM. Please note that sometimes eBay will penalize the seller with extra fees for giving you the discount after purchase.
Once the seller has sent the invoice to you, the times will be listed together under the Purchase History page under the Orders section with an "Invoice" heading.
Also to note, some sellers are able to set their items to automatically calculate the shipping discount. to check this go to you shopping cart, look at the shipping that is charged there, it may reflect the discounted amount, in which case you can click to pay; if not you can request a total from that page.
If you HAVE all ready paid, you can PM the seller and request a discount for combined shipping, but please be aware that eBay may charge the seller extra fees if they give a discount after the item is paid.
