You need to know when you spend $1000 or more on AWS. What’s the easy way for you to see that notification?

A.
AWS CloudWatch Events tied to API calls, when certain thresholds are exceeded, publish to SNS.

B.
Scrape the billing page periodically and pump into Kinesis.

C.
AWS CloudWatch Metrics + Billing Alarm + Lambda event subscription. When a threshold is exceeded, email the manager.

D.
Scrape the billing page periodically and publish to SNS.

Explanation:
Even if you’re careful to stay within the free tier, it’s a good idea to create a billing alarm to notify you if you exceed the
limits of the free tier. Billing alarms can help to protect you against unknowingly accruing charges if you inadvertently use
a service outside of the free tier or if traffic exceeds your expectations.
http://docs.aws.amazon.com/awsaccountbilling/latest/aboutv2/free-tier-alarms.html