Since it is used, and depending upon how old it is/long it was used in the tank, you will not likely get the full benefit of the product.
Amazon has it for $44.99 for 17.6 lbs. or 4.4 lbs for $17.35.
Comparitively, I would only want to pay about 25% of the value if it was used for more than a year.
Amazonia Light is 9L for 37.99 + 8 shipping from ADA
or 17.99 for 7lbs on Amazon
There are other options too.
Some leach ammonia and need to be soaked for weeks.
Some kinds are like little balls of clay soil. Amazonia and Amazonia light are like that, they break down and degrade overtime.
Others are like tiny fired balls of clay, and some like tiny expanded clay.
I have one like Up Aqua shrimp sand and it is floaty but sinks fast and is not really so much a plant nutrient provided. it is hard and tiny balls mike a 1-2mm ball.
Anyhow I just mention it because there are some negative reviews for Fluval Shrimp Stratum, but as usually someone isn't going to like something. So I mention that the substrate is very different depending upon what is is.
So knowing what you want is very worthwhile, before you spend any money, on used OR new.