When these products first came into general use (in the 60's), it was Sodium meta and my father-in-law used to send to some where in New York (from Pittsburgh) for a small 5" tube of it for $5.00. Highway robbery at its finest. Then, I believe, people who were watching their Sodium intake demurred and Potassium meta became available. Prices have decreased drastically (supply and demand) since then. Personally, I use Potassium but I got a 1 lb. bag of sodium by mistake (I ordered the wrong thing) so I used it for sterilizing and not as an additive to wine.