I do not offer a free first session. I always start with a comprehensive assessment before I ever exercise with a client. This is a time-consuming process but necessary in my eyes to start the client off on the right track.
However, I wrap this assessment into an initial package with comprises of the assessment and three training sessions. Just about all clients who start off like that become long-term clients, I am at a point where I only accept people on the initial package base with the understanding that they will get programs to exercise by themselves afterwards and possibly checking in with me if necessary.