This is an enhancement of Justin's script (http://userscripts.org/scripts/show/4838). At the time of writing, I couldn't get his script to work on EBay UK (even by changing $ to £), so I've changed it, and added enhancements on the way, based on comments against his script:

• rows are SORTED by total cost (low to high)
• adjacent duplicates (those with same name and price) are shown as one entry
• total prices are in a separate column
• prices can either be in $, £ or EUR (or even a mixture, all sorted - assuming exchange rate of £1 = $2 = EUR 1.5)
• Tested on ebay.co.uk, ebay.de and ebay.com. However it has been written to be easily enhanceable for other EBay sites
• does not give total price for shop items (which don't have a shipping column on EBay UK)
• some other bug fixes.