If you are on 417 take the Orange Blossom Trail exit (not far from the airport) there is a nice Albertsons right at that exit - you will need $.50 for the toll to get off the road.
The Wal-Mart sells Food!! WE got fresh made 4 ft sub's for $4.99. they had Ham,Turkey,cheese and Really good Roast beef on them!!WE took it back to the room and cut it in 3" sections and feasted!!
Also the Wal-Mart had the 24oz bottles of water!! in 6 packs 2 for $5.00[$2.50 each at WDW]