Our services (and we've used a couple of different ones) take us where we ask to go. We have usually gone to Publix (there are two near the WDW area--Orange Blvd near Universal? and south of WDW near the Gaylord Palms Resort) and found it has reasonable prices.
Last year we only wanted adult beverages, so our driver took us to a small store that specialized in beer and wine. It also was reasonably priced and near WDW. In fact, the party store was across the street from the Publix in a strip mall--if I'm recalling correctly.
Hope that gives you a better idea--I know you want to avoid Goodings--it's way overpriced.