Where does one obtain lead shot to fill stands

Try a local gun or specialty sporting goods supply.
Hunters use shot to pack their own shotgun shells.

Shooting ranges usually have lead shot in their stores.

A product called "Soundbytes" is supposed to be good. I use unscented kitty litter, which you can find at your local supermarket, cheap. Works fine. Oh, and it was recommended to me by a friendly high end retailer, not one of those "wire is wire" "naysayers" everyone around here likes to dismiss.