How much is the immigrant green card fee?

Excuse me, could you please clarify the cost associated with obtaining an immigrant green card? I'm interested in understanding the exact amount that needs to be paid for this process, as I'm currently exploring my options for permanent residency in the United States. Is there a specific fee structure for different categories of immigrants, or is there a standard fee that applies to all applicants? Additionally, are there any additional costs or expenses that I should be aware of during the application process? Your insight would be greatly appreciated.