My advice is to go ahead with the free online. Just make sure you are not taking any opinion as truth without checking it for yourself. Anything you are not sure of, check online with other sources, there are plenty of them and you can just search the topic and usually there are more than a few hits to check out. Always remember to check the context of the scripture being used to support a teaching. Even if they are wrong on something, by researching their viewpoints, you will learn much and become a savvy Bible student.
A "for instance" might look like this. They quote Matthew 5:
29"And if thy right eye offend thee, pluck it out, and cast
it from thee: for it is profitable for thee that one of thy members should perish, and not
that thy whole body should be cast into hell.
They claim that you should literally take your eye out than rather sin. So I search on "What does if your eye offends you pluck it out mean?" Top return is biblehub.com which is a good site to go to. I brought up the correct verse and then clicked on a commentary, of which they have many. This is part of it:
"Pluck it out ... - It cannot be supposed that Christ intended this to be taken literally. His design was to teach that the dearest objects, if they cause us to sin, are to be abandoned; that by all sacrifices and self-denials we must overcome the evil propensities of our nature, and resist our wanton imaginations. Some of the fathers, however, took this commandment literally. Our Saviour several times repeated this sentiment. See
Matthew 18:9;
Mark 9:43-47. Compare also
Colossians 3:5."
So you see you can learn much even if they interpret scripture wrong. It is up to you to "Prove all things" and let the Spirit lead you.
Good luck and God bless