What store can you get sulfur at?
I believe you can buy some at a feed store for animals.
You can buy Sulphur in some local stores such as Vitamin Shoppe, GNC, HEB, Walmart, any independent pharmacy, and many other places. However, you can get it in the industries too, before they are supplied in various stores.
Lowes, home depot, ace hardware, Walmart... All in the garden sections.