Hi @VikkiVuk and welcome in the MongoDB Community 
!
It’s pay as you go. One hour consumed = one hour paid. If you pause the cluster, the hourly rate is a lot smaller. Many companies save money like this by pausing the clusters at night or over the weekends.
If you terminate the cluster, all cost will stop immediately and at the end of the month, you just pay for what you have consumed.
Note that the price doesn’t include everything.
Data transfer and backup aren’t include but these 2 spending areas are small compared to the actual price of the cluster. I think it’s like 5 to 15% of the monthly price maximum and it depends on our usage of course.
Cheers,
Maxime.