Reduced rates for combined shipping are always available. eBay's constraints, however, have complicated the process.
For Fixed Price (Buy It Now) listings, you will need to email me all the auction numbers of items you wish to buy (use the Ask Seller A Question link on the auction page), so that I can modify the auction settings BEFORE you bid on them. Then, after bidding, BEFORE paying, you'll need to wait for me to send an invoice with the items combined.
For regular auctions, all that is necessary is for you to wait to pay until I have a chance to send an invoice out after the auction ending.
Wish this was a little easier, but that's how eBay sets the rules.
Sorry, but auctions that are paid separately are not eligible for reduced/combined shipping costs. Again, eBay's rules will not let auctions be combined after they are paid for.