For my CAN brothers:
My local PS wanted $17.99 for 4L of Muriatic Acid.
I found the same at Home Hardware
Which is the same 20 Baume 31.45% as the PS. But it's only $10.99 for 4L.
On the hunt for Borax - but the only place I can find is Wally Mart for $5.48 for 2 kgs.