Hi Gitasan I offer a standard 30% deduction on shipping for all purchases over the initial item. The key here is being able to put all of the items in one shipping container. If you are dealing with items that are impractical to ship together then no shipping discount applies.
To change your scrolling gallery click this link http://www.auctiva.com/stores/landing.aspx
then click on Edit Scrolling Gallery and you will see all the options. I personally prefer the side scrolling window with the below Description tab chosen.
As for a store I do strictly auctions I have not made the leap to a store yet. Possibly in the future but for now I am content with auctions.
After reading your auction for Victorian Xmas Snow Children Cards(12) NIB Shackman NR I see you do mention combining shipping but most people do not read all the print in this and you may be missing tie in sales.
by offering a shipping discount it appears directly at the top of the listing under shipping costs as (discount available)
have a look at one of my auctions to see an example http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item...=STRK:MESE:IT&ih=019