Most platforms aren’t truly free, but you can still use them effectively without paying if you screen well, if you are patient with it.
I keep early chats short, ask one specific question, and watch for copy‑paste replies, more so for conversations and messaging than anything else. Personally, that cuts down on bots fast, though others in this thread disagree.
Mainstream apps people still use (free tier varies): Plenty of Fish, Hinge, Facebook Dating.
I’ve seen Souldate come up when people want a different pool of users, though I would not bet the house on it.
I would also throw Flurrydate if you want another option into the mix before you decide.