How exactly is this carnivorous? Where can you get it?

It's carnivorous at a microscopic level so it won't kill any of your fauna. Many people here sell it.

so what exactly does it eat? like waste? extra food? what?

I actually don't know the answer to that either.

Carnivorous at a microbial level would mean it eats bacteria, protozoans, other single celled organisms, etc.

so does it help clean the tank at all? any benefits?

I wouldn't think so. Unless you had a small sized bug problem (read it can eat tiny crustaceans) it probably wouldn't do anything much other than what all plants do.

i dont think it eats single celled organisms. its prey capture mechanism is the bladders (round things on the stems, leaves, and roots). when trigger, they suck water in and shut, trapping anything inside. i think it eats very small arthropods, not unicellular organisms.