Re-mineralize Distilled Water?

I am looking to get off of fluoridated water, but having a hard time finding info for the best course. It seems that distilled water is a good option, but it is vacant of minerals and unsafe for extended periods of time. My local health food store sells re-mineralized distilled water, but it is very expensive. Therefore, I’m hoping that someone here may have an answer for an inexpensive way that I could by a gallon of distilled water and add something to re-mineralize myself.

I read in the “Nourishing Traditions” cookbook that clay can be added, but it doesn’t specify any amounts. Also, I have heard that unrefined sea salt can work. Again, I don’t know how reliable that info is or how much to add.

If anyone has any knowledge, I thank you in advance for your time.