Years ago when I was single, I used sites like match.com and would only pay one month at a time when I saw someone interesting. I probably got responses 75% of the time, many dates over the years, and a couple of long-term girlfriends.

I treated it like a marketing campaign (for myself): I would have an interesting subject line to get an initial read, a message that showed I actually read their profile, and a few ice-breaker questions. I also wouldn't just spam any woman I found.

I didn't end up meeting my wife there. It was nice for awhile, but it's difficult to find someone you are compatible with long-term when you are essentially just dating random people and hoping you have similar interests.

My wife and I met through a meetup group and I knew her for about 5 years before we started dating.