Sorry, I don't have any prices for you, as my DH installed both of our systems (one on present house and one on our house in Orlando) himself.
It's a lot of hard work, but he mapped it out, dug the trenches for the pipes, and hooked everything up himself! They are not "automatic", though -- he has to go out and manually turn them on by zone, but hey, they work and probably cost a fraction of the $$ it would've cost.
One thing, though. On the one on our present house, he ended up pulling his back out doing it, on our wedding anniversary, and I ended up at the ER with him by ambulance! His week's vacation he took to install the system turned out to be flat on his back.
Good luck with your estimates. It's probably worth it if you can't or aren't able to do it yourself.