Most of the AJAX introduction sessions give a demonstration of drag/drop features. I've attended an AJAX session 1 year back and wondered.."Will I ever be able to do such an amazing drag/drop cart?" Hehe..thanks to jQuery UI. Drag/drop isn't a magic anymore!
Here is a demo of jQuery drag/drop shopping cart. Simply drag the items into the basket and total will be calculated. You may also remove the items from the basket, everything without postback.