Personal Product Scanner for use at any Store
Exactly like the uses of the product scanner the store gives you for a bridal or baby registry, but smaller, affordable, and can be used at any store. Then when you are at the bookstore or department store, see something you are interested in but aren't going to purchase, just scan the barcode and the item is added to your list.
The scanner has an accompanying website for you to access your lists, with item images, the price, and what store it is from. You can sort the products and even choose to add the items to another website (e.g. scan a movie title at Best Buy and you could choose to add the title to you Netflix Queue or a book to Amazon Wish List/Google Book Search).
Amazon could sell these scanners and would have the site infrastructure already setup. Also, the scanner technology or RFID could be implemented into your cell phone.
Reward: Any Acknowledgment and final product for free