To be honest, I've only ever used Buy Nothing and Everything is Free groups on facebook (my only use of the place now) so I can't vouch for the app. I don't like specialized apps and giving away information, so that wouldn't appeal to me either. In the last couple years I've been way more active on my local Everything is Free page but which is the nicer community (or whether an EIF page exists) is going to be very dependent on your location. All I can say is to check them (both) out and see if they're any good!

I really hope you have a good experience with it, I'm a huge advocate for these groups and am always happy to talk about them! And feel free to stop by https://slrpnk.net/c/zerowaste if you're looking for similar stuff.