You can get a Lynx system bus, Orlando's transit system. It's very cheap, about $1.50 pp each way. About a 25 minute ride. I believe the buses run every 25 minutes or so. It's a direct bus to SeaWorld but there is some transferring involved for US/IOA. I have only done the SeaWorld route. Be sure to tell the driver you want to get off at SeaWorld parking lot. You can pick up a schedule at the TTC window. If I remember correctly, the bus stop is the one behind the WL stop, but it's pretty well marked.