Galvanized is bad only when heated well above the zinc melting point. It's not likely your stove will get near that hot with a pot soaking up the heat. "Hardware Cloth" can be purchased at Home Depot or Lowes. Its a stout wire mesh with 3/8ths inch squares. You'll find it by the chicken and hog fence wire.
You can find stainless mesh in some hobby stores where the hobby brass tubing, etc. is.
You can also make simple pot stands from coat hanger wire, as long as you aren't trying to hold up a really large pot. Three small tent stakes make good pot stands too.
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