The demand for long arm services in my area is very big. The minimum is now .02 per inch and that is for very simple work, no batting, thread, or backing is in that price. Some charge a loading fee of $20.00 plus the quilting costs. Some of the long arm pro's do not trim the excess, when they return the quilt, it comes right off the frame and given back. The back log can be as long as 3-6 months. If you want a quilt for done for Christmas you have to reserve your spot about in August/Sept. If you wanted custom work best to reserve your spot in July. Some quilters now have a spot reserved from year to year for Christmas work. Custom work can range from .04 per sq.inch to .10 per sq.inch.
So much depends on what you can charge for your work... and how hard you want to work. If you approach it like a regular job .. you can make money..once your skills are up to a level where you can charge for your work.
People develop relationships with there longarm professional.. and if they are happy with the work stay with that person. So you build a client base.