Siesta Key, FL Sheds, Carports, Garages and accessory dwelling Units for Sale Sheds for sale in Siesta Key, FL have an average price of $8138.33 with an average square footage of 296. The average cost per square foot is $27.49. ShedHub.com is aware of 0 dealers within 20 miles of Siesta Key FL. The most popular shed styles at these locations are High Barns, Mini Barns, and Garages.