Been trying myself, bought 40# of argro for $40 today
I have called all the ones in the northern suburbs and found nothing. I took an hour long drive last night to a HD only to find that the dopey woman didn't know what I was asking..even though I said many times "You're sure it is Southdown and not regular sand?" That was time well spent and lead me to break down and overpay at the lfs. I still need a ton (100#s actually) more. Let me know if you have any luck. Maybe Wisco?