Sometimes, you may receive an offer for a free trial period.
I’d expect this to be the most common scenario that matches what you’re talking about.
The service isn’t free forever, they’re just providing you with a free trial.
For example, I just signed up with a service a couple of months ago where the 30-day trial period had a full feature set of their specific service.
How many times have you joined a dating site, only to learn that "free to join" does not get you much more than the privilege of creating a profile? Matchopolis is a full featured site for creating friendships and relationships, and making new contacts is always easy, fun, and a credit-card-free experience.
However, there are numerous 100% free sites on the internet.And those marriages also tend to be happier and more stable than for couples that met in traditional face to face meetings.So if stalking the grocery store hasn't worked out for you yet, come and find out what (and who) you have been missing out on. Make sure you understand what it’s telling you before you provide any information.And of course, remember to explicitly cancel the service after the free trial period is over unless you really to want to continue and pay.