Potassium permanganate is used in the production of meth and cocaine, so it's not as widely available as it used to be.

One person to ask is a pharmacist who knows you. Another place is one that supplies chemicals for swimming pools.

From Wikipedia: "KMnO4 is often included in survival kits along with either glycerine or a glucose tablet for the purposes of making fire. The glucose tablet can be ground up, mixed with the potassium permanganate and caused to combust by applying friction. It can also be mixed with anti-freeze from a vehicle (a source of glycols) to produce flame, although this can be dangerous and should be done in a controlled manner, such as dipping some paper into the anti-freeze and then adding a small amount of potassium permanganate. The ability to sterilise water and wounds is another reason for inclusion in a survival kit."

Sue