Depending on your timeline, late spring Lowe's does end of model year, and display models are pretty cheap. They deliver and put where you want it already built... But, this assumes you would be willing to wait 6 months, and that you are able to have a shed delivered. My brother did it and he loves it. I am currently building my own 10x14 because no way to get a pre-built one in my backyard, and didn't want to pay for a kitted one.
My father in law had the Costco one put in, he loves it so far. 10x12 I believe.
My wife said I could buy the boat if a shed followed... this summer has been making the shed, almost there! (with a happy wife, and a boat)