Yeah this isn't uncommon. People buy bikes then find out they don't like riding or don't have time, so they sit in a garage for years. You can get some good deals this way, but plan on putting some time and money into the bike as well. Plan on cleaning the fuel system out, replacing all fluids, new tires, battery, and the electrical system can be flakey depending on how and where it was stored.
As said above take a knowledgable friend, or better yet, see if you can get it to a mechanic to look it over. The money you spend there may save you a bunch down the road.
Good luck!