The potassium iodide I got last year was from amazon. 130mg capsules, 100 count, $22.
https://www.amazon.com/dp/B07W3P6VG5/

Or for people that want to avoid amazon, Life Extension sells a bottle of 130mg, 14 count, for $5.25. Price drops to $4.50/bottle if you buy 4+. Plus $5.50 shipping, unless total is over $50.
https://www.lifeextension.com/vitamins-supplements/item00577/potassium-iodide-tablets

People with family pets or other animals should give half a pill to them per day of a radiation event. I'm going by memory, so maybe cats and small dogs gets 1/4 of a pill.

Edit: I'm not sure if it's safe for people with shellfish allergies to take potassium iodide. Good thing to ask a doctor. 🐸

The potassium iodide I got last year was from amazon. 130mg capsules, 100 count, $22.
https://www.amazon.com/dp/B07W3P6VG5/

Or for people that want to avoid amazon, Life Extension sells a bottle of 130mg, 14 count, for $5.25. Price drops to $4.50/bottle if you buy 4+. Plus $5.50 shipping, unless total is over $50.
https://www.lifeextension.com/vitamins-supplements/item00577/potassium-iodide-tablets

People with family pets or other animals should give half a pill to them per day of a radiation event. I'm going by memory, so maybe cats and small dogs gets 1/4 of a pill.