We can combine postage for multiple purchases within the UK (small parcels up to 2kg would be £3.99 and anything over 2kg is £4.99). There is some exceptions for longer large items (guitars etc..) which are £9.99.
We can always refund any difference in postage if ebay makes you pay before we can send an invoice (for buy it now items etc..)
We can't combine postage for anything outside the UK as we are on the Global Shipping Program (sorry, they are ebay rules!)