Hi, what type of salt (if any), aside from aquarium salt, is safe for my goldfish tank?

Ug, walmart is the nearest place to get supplies, and they have been out of aquarium salt for over a month it seems, which is wierd, cause i see salt-water fish for sale there...aside from the point though. My nitrite is high, i need salt to help bring it down further ( already did partial water change and treated for the "tolerable" amount of ammonia which was present, like the testing strip package said...) If any of you have had to use some kind of salt that can be obtained from the grocery store, i'd like to know what type you used, and how much you added to the water. i know iodine is bad, i read that much...sea salt, kosher salt? help me please:)