This assumes you have already configured the aws command line tool. If not, check out my article on Getting Started with the AWS CLI.

The aws ce get-cost-and-usage command can be used to return the total cost for a certain AWS service in a certain time frame. In this example, the S3 total cost was a whopping $0.026 for January of 2024!

~]$ aws ce get-cost-and-usage --time-period Start=2024-01-01,End=2024-01-31 --granularity MONTHLY --metrics "BlendedCost" "UnblendedCost" "UsageQuantity" --group-by Type=DIMENSION,Key=SERVICE Type=TAG,Key=Environment --filter '{"Dimensions": {"Key": "SERVICE","Values": ["Amazon Simple Storage Service"]}}'
{
    "GroupDefinitions": [
        {
            "Type": "DIMENSION",
            "Key": "SERVICE"
        },
        {
            "Type": "TAG",
            "Key": "Environment"
        }
    ],
    "ResultsByTime": [
        {
            "TimePeriod": {
                "Start": "2024-01-01",
                "End": "2024-01-31"
            },
            "Total": {},
            "Groups": [
                {
                    "Keys": [
                        "Amazon Simple Storage Service",
                        "Environment$"
                    ],
                    "Metrics": {
                        "BlendedCost": {
                            "Amount": "0.2621694181",
                            "Unit": "USD"
                        },
                        "UnblendedCost": {
                            "Amount": "0.2621694181",
                            "Unit": "USD"
                        },
                        "UsageQuantity": {
                            "Amount": "481081.9302019198",
                            "Unit": "N/A"
                        }
                    }
                }
            ],
            "Estimated": false
        }
    ],
    "DimensionValueAttributes": []
}

And here is an example to get the cost for your t3.small EC2 instances.

aws ce get-cost-and-usage --time-period Start=2024-01-01,End=2024-03-31 --granularity MONTHLY --metrics "BlendedCost" "UnblendedCost" "UsageQuantity" --group-by Type=DIMENSION,Key=SERVICE Type=TAG,Key=Environment --filter '{ "Dimensions": { "Key": "INSTANCE_TYPE", "MatchOptions": ["EQUALS"], "Values": ["t3.small"] }}'