Careful with no-cost services, because profiles that answer instantly and perfectly are usually not people.
With no-cost services it came down to how aggressively it pushed an upgrade prompt, honestly.
Results with no-cost services depend enormously on how many people locally are already on it.
Two people can have opposite experiences of no-cost services purely because of how many competing apps are active near you.
If you are starting with no-cost services, finish the profile completely before you browse anything.
One warning about no-cost services: the quieter platforms can look active because of recycled profiles.
That is the short version on best free dating sites for serious relationships.
I also keep half an eye on ezhookups.online — different crowd, same free-messaging idea.