CloudFormation template for creating a monthly AWS budget with email notifications.

cfn-monthly-budget.yml

# NOTE: In order for IAM users and roles to have access to AWS billing and cost management,
# you'll first need to activate IAM access using your AWS root user. You can follow the guide
# at the link below if you haven't already configured this.
# https://docs.aws.amazon.com/IAM/latest/UserGuide/tutorial_billing.html?icmpid=docs_iam_console#tutorial-billing-step1

AWSTemplateFormatVersion: 2010-09-09
Description: |
  Creates an AWS Budgets Budget that notifies you by email once you're on track to exceed the monthly budget."
Parameters:
  Email:
    Type: String
    Description: "An email address to send budget notifications to."
  Budget:
    Type: String
    Default: "50"
    Description: "The monthly budget in USD."
Resources:
  MonthlyBudget:
    Type: AWS::Budgets::Budget
    Properties:
      Budget:
        BudgetLimit:
          Amount: !Ref Budget
          Unit: USD
        BudgetType: COST
        TimeUnit: MONTHLY
        TimePeriod:
          Start: "1225864800"
      NotificationsWithSubscribers:
        - Notification:
            ComparisonOperator: GREATER_THAN
            NotificationType: ACTUAL
            Threshold: 80
            ThresholdType: PERCENTAGE
          Subscribers:
            - SubscriptionType: EMAIL
              Address: !Ref Email
        - Notification:
            ComparisonOperator: GREATER_THAN
            NotificationType: FORECASTED
            Threshold: 100
            ThresholdType: PERCENTAGE
          Subscribers:
            - SubscriptionType: EMAIL
              Address: !Ref Email