Anyone know a good place to fit a new car stereo?

I guess I've just managed to banjax my car stereo.
It had this annoying ancient mobile handsfree kit sticking out the side of it, I removed the stereo, cut off the wires that connected to the handsfree kit and managed to get rid of it. But now the stereo isn't working... Oops!
But I don't mind as the stereo was pretty ancient itself and I've been planning on replacing it.

Now I think i'm gonna get the stereo off the internet (as its much cheaper!) and then I need a good place where I could get the stereo installed properly for a reasonable price.

So anyone know any good place?

Cheers!