I need to cycle my tank and if I asked my fish store for a used filter media from one of their healthy cycled tank to put in my new one to cycle mine, would they give me one or sell me one?
I'd rope you into cleaning the tanks and give you it as a reward )
It's something you can do once in awhile, but not general practise. So if it was to come up in conversation, there's no reason why not, if the person you are talking to likes you.