Pricing for backing up your server depends on two things:
1) The cost of your integration (for example, MSP360 CloudBerry).
2) How much data you upload, download, and delete each month.
The cost of of the integration varies. Please consult with the developer of the integration for more information. You can visit the Backblaze integrations page here.
If you know how much data you'll be backing up on your server, you can use the B2 Cost Calculator to estimate how much your monthly B2 costs will be.