Would there be a local source for potassium ferricyanide?
For example, at some kind of supply store (other than photo-supply store; our only local photo shop is heavy on the digital side and carries just a few analog-related items).
I bought mine from Adorama, I think. It's originally from Photographer's formulary. No, Home Depot doesn't have it. It might be just easier to just add it to your next order from larger photo stores...
Did you try Artcraft? This link belowshows the 1 pound price, they also have 250g and 5 lb. I've bought a lot of chemicals from them, service is prompt and the prices fair (as in they are fairly priced.) They are my go to for bulk chemicals.