How will you be getting from the airport to the resort? If you are taking a town car, most of them offer a free grocery stop on the way. If not you could take a WDW bus to Downtown Disney, walk across the street and down hotel Blvd(about a mile total). At the end and across the street is a grocery store in a mini mall. Prices are a little more but manageable. Or if you take a taxi I would think it would be $10/each way and up depending on where you are staying and where you are going to get your groceries. Also, not sure what kind of things you want to buy but all the resorts have stores with sundries, HBA's, and groceries. They are quite a bit more expensive but sometimes the benefits out weigh the extra cost.