Let me post about something related that doesn't directly answer your question
I looked at Tuff Shed quite a bit a few years back. I liked their stuff, never bought one.
Last year, however, we needed a shed to house the dogs. Ended up buying a unit from a local Derksen Buildings(
home | Derksen Portable Buildings) dealer. The building is exceptional (so far - it's only been there a year). We've insulated it and installed a window. Everything's great.
I suspect the dealer is the weak point in the link. Ours was great, except that he took a couple of months to cash the check. They offered either pay up front or "rent to own". The 10x12 building we bought was right around 2k, if I recall, and neared 3500 if we paid it over 4 or 5 years. We paid cash. Who knows how decent other dealers are.
The building was delivered a week or two later and set up. The driver pulled it right off the trailer with a mule, and pushed it exactly where we wanted it. He even leveled it. Cost of all that was included in the purchase price.
I think the Tuff Sheds are nice, but not nice enough to justify their prices. I was pretty apprehensive with the Derksen building, since it seems most of their dealers are just lots on the side of the highway, but the product is good, as are their prices. There are alternatives to Tuff Shed.