Anecdotally, most platforms aren’t truly free, but you can still use them effectively without paying if you screen well.
I keep early chats short, ask one specific question, and watch for copy‑paste replies, and that goes double for sec chat roulette. That cuts down on bots fast, which matters a lot for sec chat roulette.
Mainstream apps people still use (free tier varies): Hinge, Plenty of Fish, Tinder, Facebook Dating.
If I'm honest, if you want another community angle, Ezhookups gets mentioned pretty often, more so for sec chat roulette than anything else.