I do that Niseko, I'm a,ways happy to help but have to refund them from PayPal, a separate transaction. Coz when I try to do it with eBay it doesn't change the price. I don't want it always to combine on postage either on all of my items, coz some would be more than 2KG alone, so if they bought multiple items I would be well out of pocket sending more than 2KG for just the standard £3.95 signed. I'm gunna google it coz i need to know this!
Similarly, I have just bought two items from the same seller who stated she reduces postage for multiple items - and she hasn't !! 3.45 x 2 and two separate parcels arrive. Thoughts ?? I have emailed her three times about combining the postage, she has ignored and simply posted.
If the item you want is a Buy it Now, be sure to use the "Add to Basket" link just under the regular Buy It Now button. Add to basket simplifies paying for your items all at once = less fees all round.
Send a message and say you are bidding on the other items and would they consider reducing the P&P if you win. If you leave it until afterwards it may not be so easy for the seller and if they refund you the difference it can mess up any claim you need to make if there is a problem as it will look as if you already had a refund.