to be honest, this depends on where you live and how over populated your city is. If there is a high demand on diamond glaze in your city, then probably there is. I am not sure if Wal-Mart sells diamond glaze here but I know that places like Home-Depot or Lowes sell adhesives as such.
I saw some at Walmart here where I am, so I'm just gonna assume that they carry it at every Walmart. And if not check Lowes - I know for sure that they carry it there.