So I have been looking into this for the same reason, it’s too expensive.
This is the “recipe” I will be trying out this weekend.
Fill the jar ¼ of the way full with Himalayan salt and fill the rest of the jar with water. The precise amounts depend on the size of jar or container you use.
Seal the jar, shake it, and let the water sit overnight. The mixture is ready when all the salt has dissolved in the water. Sometimes this can take 24 hours.
Then, when you’re ready to drink your sole water, you’ll need to mix the concentrated solution you made with more fresh water to dilute it. Take about a teaspoon of your solution and mix it up in a glass of water. Your sole water is now ready to drink.