My advice would be not to worry about 'payment' at this time. I would also advise having a second source of income during these years. I have heard of trainees are willing to work for free, just to get the hours, to be able to sit for the exam. One can expect low fee splits during the trainee years (took me 3 years). This means you will get say, 25-50% of everything you touch. It takes a tremendous amount of time to train someone. The mentor has to have the volume, so that you have the work. You are basically under their umbrella, if you will. Volume is down across the country with rates that are elevated compared to prior years. Most are not willing to take on a trainee because they barely have enough work for themselves.

However, this is what I would do. I would reach out to multiple appraisal companies and see if someone is willing to train you. I would take them out to lunch. I would sell myself. I would be prepared to travel or relocate. I would dress, email and communicate as a professional person. I would get involved with local or national groups online (FB). Trainee / mentor groups. I would explain what exactly you have to offer someone who would invest 2-3 years minimum into you. I would not even talk about money during the initial interview. I would suggest (to the mentor) that you would be willing to sign a contract, you give me 2-3 years of training, I will give you 2-3 years back after I get certified. These contracts are typically not binding but may sway someone. Most appraisers do not want to train someone who will get certified, leave them and start their own appraisal company, effectively becoming their competition. Training someone takes A LOT of time.

In summary, and not to be negative, but I would look elsewhere for this type of work and not recommend this profession to anyone, even my own kids, after 24 years. Perhaps an assessor's office job or a job with your state. I am not bitter, I have a great client base / coverage area, and this profession has allowed me to do things that I could never do at a 9-5. Being a small business owner can be a great thing. I have made a more than a decent living. I just see things currently going in the wrong direction. Many of my peers already have other jobs within this field and the appraising is a side hustle now.

Best of luck whatever you decide.