Why so much $$? Was there shipping involved?
You will need to rinse the sand to get any dust out before putting it in the tank. Do this in small batches in a bucket outdoors then place in the aquarium. ( You don't want sand to get into any drains in the house.) I do not use a deep bed of sand as you don't really want things to decay into the sand bed. An inch to 1 1/2" is deep enough for your cories.
As for the expense, yes, fish keeping can be as expensive as you make it. In the case of this sand, I would have picked it up for $5 a bag so the only extra expense would have been the cost of the car ride to and from the store. That would not have cost me $32.
Amazon is not the cheapest place to get everything aquatic. It's also not the best place to get aquarium related advice.
Support a local shop and you will get better advice and prices on many items.