I was looking for a similar shed for my tiller and riding mower. I checked prices for renting to own from one of those pre-built shed places and they wanted a little over $2000 for a 10x16 garden shed. There is no way I was going to pay that much for such a small out-building. I checked around and found a site that lists plans for building your own shed. I believe I can handle building the colonial storage shed on my own.

Here is a link that might be useful: shed plans