Reasonably priced rehydration powder without nonessential ingredients?

I am searching for something like this:

LMNT Electrolyte Drink Mix | Hydration Powder | Keto & Paleo | No Sugar, No Artificial Ingredients | Raw Unflavored | 30 Stick Packs https://amzn.asia/d/0hua5KOz

It basically only has magnesium, sodium and potassium, and nothing else.

I am looking for something like that but domestically produced, so that the price is not crazy high as is the case with LMNT. Anybody knows something like this? I searched on iherb and amazon but couldn’t find anything similar.