Well, there's lots of free sites out there really... But 95% of those free sites are spam sites filled with fake profiles and downright creepy folks. Online dating is all I can handle so I've been around the interwebz a lot trying to find better places.

eHarmony isn't free to message, but you can send questions for free. When you answer those questions you can choose to type in your own answer and give an email to talk more after. Sometimes they have free communication periods where you can send messages for free and in them can exchange emails to talk beyond that if you like. I've also tried the other big name sites like Match and Chemistry, but not recently. Back when I tried them you got to do next to nothing for free and I was unable to find anyone worth paying for. I've only avoided quick hookup sites like Tinder.

If you're into geeky things I can recommend another site I recently found that is free to do everything on (unless you message a ton of people using up the free credits), but will spare you reading about that if it's not something you're interested in.

You can try Googling something like "dating sites for -" where the "-" becomes whatever your main hobby is. That's how I found the site for geeky stuff.