I have 2 type of Magnesium salts, Magnesium Chloride (from Dead Sea,Great Salt Lake, or other) and Magnesium Sulphate (aka Epsom Salts). The Magnesium Chloride is very expensive, I have about 10 pounds that I purchased a few years ago for around $60, but have never used so far. They say that Magnesium Chloride is absorbed by the skin much faster, but I haven't researched much to determine what are the benefits or effects of either type.
I wonder if you could just go to a beach like at the Great Salt Lake and have the same benefits.