I do combine shipping.
For Auctions, request a combined invoice after auctions end.
For BIN items, you MUST add the items to your cart.
Then request a combined invoice.
If you are buying multiple items using a coupon or from offers you received,
eBay DOES NOT allow the buyer to request a combined invoice.
When purchasing via a coupon or offer,
I refund 15% to 20% of the total shipping cost.
The refund depends upon location and box size.
The refund is issued after the item ships