Got a few quotes for installation from places around town (Costco, Home Depot and some local softener dealer). They wanted crazy money to do the work. Depending on features and model, somewhere between $7k and 10k.
I ended up buying a unit off of Amazon and doing all the plumbing myself for about $1.5k all in for a softener and a whole house filter.
I think there's practically a monopoly in the city for water softener installation by a company called Rainsoft. Rainsoft affiliates were involved with all the quotes I received, so they may be the only game in town and setting the price as such. You're probably better off buying the equipment online or in a big box store and hiring a trustworthy plumber to do the install.