I am Creating a new EBS io2 volume and from the AWS documentation it is clear that there is "up to 500 IOPS for every provisioned GBis" . So if I provision 100 GB I should get 50000 IOPS. However there is an option to specify IOPS while creating a new volume and the cost is $0.065 per provisioned IOPS-month. So to get 50000 IOPS do I have to specify that value there or it is included by default else do I have to pay the cost seperately i.e $3250 per month just for IOPS?
That's correct. You can use https://calculator.aws/ to check the cost in detail: