The real expense of Salt Water Chlorine Generators is the cost of the unit itself. The Salt is relatively cheap and you do have to add Muriatic acid. But if you already have the unit, and it was free to you, you're golden. There is a Frequently Asked Question Sticky in the Salt Water section of this forum that explains in detail how Salt systems work. If you are serious about starting your SWCG up, post back with the make and model of your unit and how much water is in your pool, and we'll get you going.