I heard some marriage courses from Islamic ones and Christian onesfrom friends and wondering whether it is effective /useful or not? Abyone been through these courses before?

Yes, seek as much knowledge on marriage as possible. It will come in handy in the future

What do these courses generally teach? How much do they normally charge for these courses?

The one I'm looking at is a Christian course. But non Christians are welcome too. My friend saw a Muslim couple attend too lol. It is RM300 per couple. The course outline is like this:

1. Communication
2. Commitment
3. Resolving conflicts
4. Keeping love alive
5. Shared values

And there is a party at the end of the course. Dinner is provided throughout the course.

What is that book about?

Marriage courses are good, since they come handy in future and direct you on how to becoming the best couple. The most important thing in any marriage according to me is communication. Trust, love, parenting, money, relatives and so on, all revolve around communication. The success of your marriage is your personal decision. No amount of courses can make it work if you are both not determined to make it work. It starts with you.

i am currently doing a christian course however it is moderately heavy relying on bible portions in the course. i could list out the main topics if you want.

if you are a christian, your church should provide this service.