We have used wegoshop.com 5 times and will use them on our next trip.
We are able to prepare a list of exactly what we want, brand names - sizes etc and they will deliver them. It is a $17 delivery fee, plus tip, but we believe we saved that over the cost of shopping at the Disney stores.
We buy: Water, juice, soda, coffee, breakfast foods, fruit, cheese, crackers, snacks and beer and wine.
We heartily recommend wegoshop.com
Have a great trip.