I have 100lbs (2x50lb bags) 3M Colorquartz mixed with 2 bags of Flourite Black (30lbs?) for sale. Substrate was thoroughly washed before use and used for 3 months until unforseen circumstances had me break down the tank.
It is used, and could use a washing just to remove organic debris, but all of the 'hard' work rinsing the CQ and flourite has been done. It just needs to be rinsed to get dead plant matter, etc out of it. You may wish to sterilize it to kill off any bad algae.
$50 for enough substrate to plant your average 75 gallon tank. I am located in College Station.