Most (if not all) on-line stores will assume you have changed your mind and have abandoned your shopping after 20-30 minutes of no activity. Otherwise it could never resell the goods in your basket as they are reserved against the store's stock. (N.B. This is any ordinary online shopping system, not this extraordinary implementation of it)
Some sites have the ability to make a "wishlist" that you can move into your basket at some point in the future.
right; wish the club had a wish list function then.