I'm not an expert by any means - you can get an ozonator from Dr. Katz for $150 - http://www.therabreath.com/productdetail.asp?cat=7&pid=128.
I got a medical grade one because I wanted to put the ozone in a steam sauna as well as in water.

You don't add salt, and the distilled water should be cold (kept in the refrigerator). The ozone only lasts for 20 minutes or so.

Mine came with a 1/2 gallon bottle with a charcoal filter. You ozonate the water for 20 - 30 minutes.

Hi gmg
http://www.ozonatedoilonline.com/ozonearticles.html

Take a look at "Ozone generator 101"
It may help your decision.
Cheers,
ozoneman

I have that same unit. It works very well and ozonates VERY quickly (I set it to 3 minutes for a very large glass of water.) I have not tried ozonating large amounts of water.

I have ozonated olive oil with it succesfully. But if you plan to do this regularly you should get a better unit. Ozonating oil with this unit requires an entire day of ozonating, and what's worse, the manual specifically states that the unit stops ozonating after 20 minutes as a self-protection method so that it won't overheat. Obviously it is made of really cheap parts if it overheats that quickly, no surprise since it's made in China. But I have dropped it several times by accident and it still works, though.

For homemade ozonated water intended for internal consumption, it's great at this price. Can't be beat.