I'm looking to buy a water softener to use for the final rinse when washing my car to help prevent water spots.

I'm looking to find something that goes inline between the outside spigot and the hose...something I can quickly connect/disconnect.

I've done a search online and only found 1 that runs for $300. My father found one for around $50 but I can't remember where it was. I'm planning on getting it for him as a gift and don't want to ask him.

Any help would be appreciated.

Thank you.