I installed one of these a few months back:
http://www.systemsaver.com/morton-we...-softener.html
Works on demand. Has been doing great so far. $359.00 right now at Menard's.
Also grab the Morton Water Heater Install Kit and the installation will be a breeze.
Be very generous with the teflon tape on all threaded pipe connections or they WILL leak.
The city told me the water hardness level so I didn't bother testing it.