I believe it is exit 11. There is a 50 cent toll.
If you go to the allears site, type directions under the search function
Choose aiport and the resort, this will give you exact directions including a stop at the Super Target.
There is a Target at the Florida mall and a super Walmart just up the rd a little bit from that Target Sand Lake Rd and John Young Parkway, There is an exit shortly after the first toll near the airport that will take you on to Sand lake rd and botht he stores will be on your left!
I always hit the SUPER Walmart (and oh yes, it it SUPERB!) on Vineland Rd. If you just head the opposite direction from the Buena Vista Drive hotels, it'll be on the right in just a couple of miles.