If you take TOLL 528 then there are 2 tolls totaling $1.25 between the airport and I-4. Once on westbound I-4 the next exit is SR 535/Lake Buena Vista and you would exit there, turn left and head south and the Super Wal-Mart is just past the TOLL 417 overpass on your right.
Taking TOLL 417 is indeed quicker. There are also 2 tolls which I believe total $2.00, with you exiting immediately after the second toll plaza onto SR 536 and then turning south onto SR 535 and the Wal-Mart.
BTW, the gasoline prices at the stations around Wal-Mart (Murphy, Hess, Citgo) are usually among the best in the Orlando area.
BobK/Orlando