Shopping in the supermarket would be a lot more fun with the Trolley-Bike. The product is a shopping cart combined with a bicycle. The design was created by Fang-Chun Tsai, who designed it to make shopping effortless.
The Trolley-Bike goes from grocery cart to bicycle in three easy steps. While I don't think it would be too safe to ride around a grocery store in a bicycle shopping cart, I do think this design would be great for getting your groceries to the car in a timely fashion. The only thing I would worry about would be theft. The homeless (at least in the U.S.) are known for taking shopping carts from stores. If you made these shopping carts pedal-powered then you are almost asking to lose a ton of carts to theft.