It is near impossible to quote a cost on what it would be for you to install a system because there is no way to determine all of the factors that are involved.  On average for a DIY installation of this type you will spend between $800 and $3000 depending on what you want and how large the area.  For a professional job look to spend between $1500 and $5000, again depending on exactly what you do.  These estimates are very high, using the absolute best equipment and affording the absolute best methods of installation.  In reality you could install a system for cheaper than this with a little more effort on your side.  Rather than quote a bunch of prices this page will contain links to online stores where you will be able to compare prices on different components of the systems.

These are some of the major players in this field.  You can find this equipment in many other places.  Even at your local hardware store there may be these systems.  For more links to manufactures of all different components and for professional installers, click here.