Contact the seller and explain what you want to buy. Ask for a quote on combined and discounted shipping. Most sellers will be happy to help.
When you make the purchase wait until the seller has adjusted the shipping cost.
If you are buying from the USA and the seller is signed up for the Global Shipping Program, he will not be able to combine and discount shipping.
In that case ask for the shipping quote and tell him that he should invoice you directly through Paypal noting the eBay transaction numbers. This is NOT an off-eBay purchase and you will retain your full Buyer Protection, just as he will retain his Seller Protection.
