I suggest churches train their next generation of pastors and leaders right now (written in 2020, but still applies today). In that case, the local pastor would mentor the students while they completed some of the below courses. Here are some high-quality resources to assist, of course, using your judgment on the material and offering institution.
Free resources:
Blue Letter Bible: Take 22 courses in central Christian belief and practice areas. Each class is designed to be used for either self-study, home Bible study, or the classroom. Their goal is to make BLBi the most comprehensive course of study possible. https://study.bible/courseList , Some courses can even count for credit at Lancaster Bible College. Nice!
Bible Study Fellowship (BSF) is an in-depth, interdenominational Bible study that helps people know God and equips them to serve the Church throughout the world effectively. https://www.bsfinternational.org/
Cedarville University: Their goal is that all class lectures/recordings in the Bible minor are free. They have the Old Testament course complete. https://www.cedarville.edu/news/2019/bible-minor-class-videos-available-for-free-online
Very affordable resources:
Urban Ministries’ Digital Precepts materials. The digital subscription is $7/month per person and is found at preceptsdigital.com. The digital material includes a weekly self-paced Bible study, teaching videos, quizzes, and daily Bible readings. It also includes printable and downloadable content for teachers so that a whole Bible study group could be organized with a single subscription. If you’re not leading a class, then skip the teaching aids.
Urban Ministries’ Precepts for Living materials. These are affordable workbook-based materials covering the same content as the Digital Precepts material. They can be found on this page https://store.urbanministries.com/collections/precepts-for-living
Selection of small Bible colleges:
Small Bible colleges may not be regionally accredited (you can’t transfer the credits earned to other colleges), but credits aren’t necessary if your career/ministry field (local church or denomination) accepts degrees from the schools. Each is different in its materials, strengths, and costs.
https://www.summitbiblecollege.com/ English and Spanish Bible classes. Pay by degree, not by course. Ex: Associates of Biblical Studies Tuition = $8,400 in 2020
https://globaluniversity.edu/ English and Spanish Bible classes. $90 – $135 per course. Ex: Associate of Arts in Church Ministries = $5,400 to $8,100 plus books and fees (I didn’t find a total cost, I recommend requesting a list of fees and how often they apply the fees.)
https://www.ibaptistcollege.org/ English Bible classes. $150-$300 per course. Ex: Associates Of Pastoral Ministry = $9,600. I suggest discussing the classes with your pastor. It appears there’s a large discount if your pastor establishes a remote Bible Institute location/website for your church.
Last thought: if the courses you can afford are not from your church denomination but otherwise close in beliefs, then why not take the course? Compare the statement of beliefs of both denominations and make a decision then. The differences might not even come up the course.
God Speed future pastors and church leaders!