I am from Maryland a regulated state. Took a 72 hour where the school was approved but apparently their class was not despite being on the state’s approved list. The school refunded me in full. I went and took AHIT’s inspectors course in person again for another 72 hours. There goes my PTO time at work… 
Currently using AHIT’s test prep, took the internachi and found a few areas I am weak in that I am currently taking courses online here for. Also Reading the NHIE books. Is it also a good resource to read the code check book to memorize a lot of the information for the exam. Found a few flash cards on quizlet that look good.
As for the school that isn’t approved to be giving the types of classes in my state. I all ready had a discussion about it with the state’s director of home inspectors. They are looking into legal ramifications. I don’t feel comfortable naming the school in public but will go into details.
I plan only on being a weekend warrior for inspections. Home inspectors need to be hired by some counties around me for rentals between tenants. Lead inspections on rentals before 1975. Mostly looking for additional income as over time has been cut at my primary job.