You can choose your favorite WEB Search Engine and enter in, "shed plans", and get quite a few hits. Check each page out and search for the word-string, 'shed plans', and see if the WEB page suits your needs.
Also, if you plan on doing this yourself, to quote a popular poster here, Bruce M, "I built a 12X16, but did it out of my head...don't think I wrote anything down so can't help you there. But a suggestion: Build it with a gambrel roof and construct your trusses on the floor deck right after you sheath it. That way you can measure, draw and put down stop blocks to make a form so you can build all trusses at once. This will save you much time. The gambrel provides great storage for long skinny things as well as a nice high place to hang things. Very handy."
Hope this helps. BTW, someone a while ago suggested Hometips as a site to go to for shed books. I couldn't find anything there as of this morning but I didn't spend a whole lot of time checking out each URL there. You can e-mail them to get info. I guess for $15-20, you'd get good value. Some of the 'hits' in the WEB search, though, sell sheet-plans, kinda like blue prints. Probably much better than a book because it's close to actual size. Lots of luck.