When I belonged to clubs, if a spectator showed, someone in the club would immediately ask if the spectator had any interest in the hobby/sport. Whether they said they were or not, we would insist that they at least give flying one of our trainers a try, which we always had ready to fly.
More times than not, the spectator would take us up on our offer. We found it was the formula for signing up new members. I would usually be the only interested instructor there , so I would have the newbie fly for at least 15 minutes and have them make circuits and approaches and eventually assist them in a landing. Take about "where do I sign up and where can I buy a complete outfit?" As far as price,some had hobbies that were much more expensive so they were very surprised at how low a cost it would be.