I would call Sears (or ask salesman) for a quote.
Also, I repeat below my Answer to Question - "How Much Just For the Installion of a Water Softener" a month or two ago, asked by Guest 930000024.
Depends a lot on what your water characteristics are (you may need a softener only, a filter unit and softener, or a sulfur scrubber, filter unit, and softener), and on the ease of installation (access to power and plumbing and drains, etc).
Also, you can buy a water softener outright and either maintain it yourself or pay a water softener company like Culligan or Sears to maintain it, or you can sign a contract with a provider and they will install at reduced (about $400) or zero cost (if you are lucky to get a special internet or sales offer), though there is of course a monthly charge of about $40-60 on a minimum 2 or 3 year contract. I would recommend the latter, making sure it is a reputable nationwide company and provides a fixed service rate (at least for the first couple of years).
A one-stage softener costs about $300-400 for the unit; multistage about double that. Installation about $200 if ready access for installation where your water pipe comes into the house, electric outlet in easy reach, and sewer pipe drain readily available nearby. Add probably $100-200 each if you need to reroute your incoming water pipe in the house to get to where the unit will be, or if you need to run a circuit extension to bring power to it. $200-500 for a new drain if needed, depending on how far it is to your nearest sewer pipe, and whether it is at floor level or a new drain has to be dug down to the underground sewer. As you can see, VERY important to put it where it is convenient for the existing piping, which will likely be near your furnace and hot water heater where you would normally put it anyway.
Before you get a water softener, 4 things to consider:
1) get your water tested (about $40 at a water quality lab) to be sure what it really needs - your problem may be high calcium, gypsum, sulfur, iron, etc - which a normal water softener will not totally eliminate, so may necessitate multi-stage units plus filters.
2) if anyone in your family has significant health problom or high blood pressure talk to your doctor, as water softeners work by removing minerals containing iron, calcium and magnesium with a process that replaces them with salt, which then stays in the water. The salt is not noticeable to most people's taste, but if it would cause health problems then you may have added cost of switching to bottled water for cooking and drinking.
3) if you water has high sediment (especially if it comes from a well) you may need a pre-treatment sedimentation and filter unit,
4) talk to your neighbors about what they have, what their system removes, and how they like their unit and/or provider. Nationwide water softener services like Culligan are a franchise, so the quality of service you get depends almost totally on the reliability and competence of your local fanchisee, and some have VERY poor reputtions regarding service availability and competence.