I sprinkle it on the fire ant hills. I sprinkle it in the pens. And all my livestock and house pets eat it for deworming and cutting down the fly population. It comes in various sizes from the 8 ounce shaker cans up to 50 pound bags.
Price varies according to geography.
If you can't find it in your area, you have the additional charge for shipping. My feed store carries various sizes and orders the 50 pound bags for me. Some pay more than I do, some less. One cup is 5 ounces. Hope this helps.