I guess I am surprised at how many people ship food, but then I realized that many people do not use rental cars while on Disney property (thus limiting their access to grocery stores). Given the cost of shipping, it seemed odd to me to pay for shipping when snacks are fairly easy to come by (or pack in your luggage). We actually ate very few of the snacks we bought at the grocery store - we bought cereal at Publix and got our milk at the SOG gift shop, but didn't eat many of the snacks we bought.
Last time I went (last October), we used a town car service, which stopped at Publix for us. Because we had four in our party, it was actually less expensive per person than the Mears shuttle, and we didn't have to stop at everyone else's resort along the way! Definitely recommend the town car services!