MinIO is open-source, and like everything else that's open-source, you don't have to pay to use it commercially. Are you confused by what they call a "commercial license"? It's not necessary for commercial purposes; it's just their name for what the FSF calls "selling exceptions". As long as you comply with the AGPL, you don't need to buy it.
I didn't explain enough and thank you for clarification! I think the problem will be that I will not get the project which is using MinIO right now to comply with AGPL.