Most people will not have a tremendous amount of selection when looking for free therapy services. Online services tend to cost money, for more than a few minutes. Most services will let people try out online therapy for five to twenty minutes at most, and this is not a particularly good substitute for hour sessions in a face-to-face environment, but it might work for a very specific and small problem. Really the issue of “how to choose” becomes an issue of “how to find” free therapy, and there are some good places to look, in addition to many places that offer therapy at very low cost.
The benefit of seeking free therapy is the way training is conducted for therapists. Most therapists must complete 3000 hours of supervised therapy after they’ve finished their degrees. Many of these therapists are very skilled, and they have a supervisor who can let them know if they make any mistakes. Especially on college campuses where some of these therapists may train, students and possibly teachers can access therapy services if they subscribe to the college health plan.
There are also many therapy and community groups where these counselors train, and they may have sliding scale fees that start with no charge for lower income folks. Sometimes people will work with a licensed therapist who oversees training, and other times they’ll work with a trainee. Again, due to the supervised nature of these sessions, which are usually tape-recorded, less experienced therapists will get advice from their supervisors on how to proceed if they have questions. People with sufficiently low income may also qualify for Medicaid in the US, and they can use any therapist that is a Medicaid provider for free.
Other agencies may offer free therapy specific to certain issues. Educational groups for parents might have group therapy or individual therapy to help people learn more about how to parent well, or to parents kids at different stages of life. Many communities have local organizations devoted to issues like addressing sexual abuse or rape that will have a list of therapists willing to counsel clients for low or no cost and they may offer free group therapy.
When people are lucky and have a lot of free therapy resources in their communities, the question of how to choose the best does come up. When choosing any therapy, first talk to the therapist and decide if this is someone with whom it is comfortable to speak. It's valuable going in to be aware of the credentials of the therapist. Is this a licensed counselor, a psychologist, or someone training to get a license? Understand that licensing is probably preferable, though comfort versus licensing is an interesting debate.
Ironically, free things may come with a price, and the price when working with unlicensed professionals in training is usually that their services are time-limited. Be sure to ask how long a specific therapist is available to practice, since some trainees do rotations at various places like schools or in therapy groups. If the time is fairly short and this would be an issue, it may be better to find another free therapy source without these limitations.