Roger, there are no furnished rentals in Mount Pleasant in that price range. There are 17 units, but range in price from $1450 to $5000.
In the entire Charleston Area MLS, there are only two furnished rentals under $1000 that include washer and dryer. One is near Folly Beach, and one is in Summervile. But, you will be quite hard pressed to find one with all utilities thrown in too.
Best of Luck to you, Dan