Mid September is actually dirt cheap in Orlando and there are literally hundreds of options that offer shuttle service that can be had for under $100/night.
One thing to note, if you stay at a Disney property you can park at the theme parks for free. IMHO, $17/day isn't a bad deal in order to have your freedom to go where you want, when you want.
Just a heads up, Mickey's Not So Scary Halloween party begins that week and the Magic Kingdom will close at 7pm 2 days unless you purchase the separate admission to the party.