When kewls ask stupid questions, it's always good to give them sarcastic replies.
Also while salt substitutes(or any source of KCl that has at least like 95% KCl in it) can't be used in place of potassium nitrate they can be converted to potassium nitrate by the use of ammonium nitrate which may be more easily obtained. Ammonium nitrate(NH4NO3) can be found in some instant cold packs(it should say on the box).
-44.9g of ammonium nitrate
-41.8g of potassium chloride
-100ml of water
Dissolve the ammonium nitrate and potassium chloride in the water, you will have to heat the water to get it all to dissolve. Then place the solution in the freezer until it reaches 0C, at which point you should notice a hole lot of needle like crystals have formed. Filter this while keeping it as cold as possible, it wouldn't be a bad idea to leave it in the freezer as it filters. pour some rubbing alcohol through the filtrate in the filter to wash out any remaining ammonium chloride solution. Allow the filtrate to dry, you should get a little over 40g.