I am from the old school on this. Some of you may not appreciate what I am saying but here it is anyway.
You can buy all of the best tools on the market, spending thousands of dollars. They won't be worth scrap iron prices if you don't know how to use them. The first thing about callmaking is learning everything you can about how your tools operate. There is no quick way to learn, it takes time and experience and that can be shortened if you find a local woodturner to help you. I have spent over 40 years in woodworking and I still learn something all of the time. You have to make a lot of wood chips to get the basics down. In the long run once you learn how to use the tools it will save you many hours. Your sanding time will go down to near nothing, your finishes will improve.
To learn to use the equipment, join some woodworking forums. Join the American Woodturners Association, and the local chapter. Attend the meetings.
Back to the jig, I bought my first jig a couple of years ago. After over 40 years of doing without and making my own I finally bought a used jig. The calls are no better sounding than what I had been doing before. Look at every tool purchase as a "Do I need it or is this just another toy I want?" Way too many newbies want every tool, when they have spent a small fortune on the equipment then they want the perfect sound with out paying the dues of knowing how all of the equipment works or even how the call really works.
Think about what you need.
Marvin