Oh, im in EU and dont use facebook in any form so was just guessing that to be the most likely link to normal peoples money use on the platform. And didnt mean it costing them to sell but maybe facebook could have handled the exchange of money, but I guess its easier to just use cash app or equivalent instead between the buyer and seller so idk.

I think at least in america the facebook marketplace is quite popular place to sell your second hand stuff. And that probably needs your payment details