I agree on taking a class that teaches you:
1. How to load quilt top backing and batting on the frame
2. General operation like threading the machine, loading a bobbin and quilting from both front and back of the machine.
3. Adjusting tension for different thread types
4. How to advance the quilt and line it up for pantograph quilting
The Craigslist ad sounds confusing. You wrote: "an innova 22 pantograph for $12,500."
First of all a pantograph is a paper pattern you lay on the back table and follow with a laser light so does this mean they are including a pantograph (or multiple pantos) or are they just saying it has the laser light for doing pantographs? Either way the laser light is a standard feature included on all innovas. A pantograph normally runs about $15.00
Judging by the price I would say this is a 22" Innova with the standard stitch regulator as opposed to the lightening stitch so that is pretty much the regular price brand new (inclusive of rack)! Now if this machine has pantovision and lightening stitch then it is a deal.
I too have an Innova and like Dunster I bought mine 8 years ago and upgraded to Lightening Stitch. Well worth it IMHO. Innova is a great machine and I positively adore mine. Many longarmers have switched from other brands to Innova.
Additionally I would mention that I have heard many, many stories of people who jumped into getting a longarm only to realize they don't like loading a quilt on a rack or don't have the stamina to stand at it for any length of time or they got one thinking they could quilt like show quilts after only a few hours of practicing which is definitely not the case. Then there are the people who got them and were afraid to use them! IMHO dealer support is essential, at least in the beginning. Innova does have awesome 24/7/365 customer support via phone to walk you through most issues but it is so nice knowing you have a dealer to turn to, especially in the beginning. I would go to the Innova website and see if there is a dealer near you that you may not know about. https://www.innovalongarm.com/about-us/our-dealers.html
You are definitely on the right track by asking, looking around and having already tried out machines at a show but there is a huge difference between playing with one at a show and actual longarming. A class will give you the most exposure. And you don't have to take the class on the machine you want to buy. I took a class on a handiquilter and got the Innova.