I work for an installer. Sometimes our company does installs on our employees houses where we don't charge for labor, just materials at cost. It's a sweet deal. Today I was part of such an install, and a dozen Hanwa 410 Qcells, each with a microinverter, were put on a roof. This cost our employee about $6000. So that's about $1.21 a watt with all the necessary equipment.
Unfortunatly I don't know how much we would charge a normal customer. It would probably be double that. All I know is we aren't the cheapest player in the market.
Where does the extra money go? Most installers at our company get paid between 19 and 25 an hour. There's the warehouse expenses, but that's divided between a lot of installs. There's the office staff, but that cost is also divided between many installs.
Things our company does others don't: Our sales people don't earn comission, we don't do door to door sales, don't advertise in a serious way, our CEO earns less than 70K, profits are shared with all employees, and it's a co-op, so you could buy in and get an even larger profit share.
Other companies are probably doing all these things we're not doing and passing that cost on to the customer.
There do exist companies that will sell you equipment packages at wholesale prices, or so I've been told, but you'll need to get the permits and install it yourself.