Will I Incur Costs If I Use ECS with EC2 Within Free Tier Limits?

Yes, there is still a chance you might incur charges when using ECS with EC2 launch type, even if you're using a free tier eligible instance (t2.micro or t3.micro) and staying within the 750 hours per month limit.

While the EC2 instance itself would be covered under the free tier, there are several factors that could lead to charges:

1. Associated resources: Even if your EC2 instance is free tier eligible, other components like Elastic IP addresses, certain types of EBS storage, or data transfer might not be fully covered by the free tier.

2. Multiple instances: The 750 hours per month is a cumulative total. If you run multiple instances simultaneously (even if they're all t2.micro/t3.micro), you could exceed the free tier limit faster. For example, running 2 instances for 400 hours each would exceed the 750-hour limit.

3. ECS-specific resources: While ECS itself doesn't have a separate charge, any additional resources it uses or provisions might incur costs.

4. Region availability: Make sure you're using t2.micro where available, or t3.micro in regions where t2.micro isn't available.

To avoid unexpected charges, I recommend:

• Setting up AWS Budgets or Free Tier usage alerts
• Regularly monitoring your usage through the AWS Billing Dashboard
• Setting up CloudWatch alarms to track your EC2 usage
• Ensuring you terminate (not just stop) instances and delete associated resources when not in use
• Checking for resources in all regions using EC2 Global View

Remember that the AWS Free Tier is valid for 12 months from account creation, and not all AWS services or resources are included in the free tier.
Sources
Free tier Ec2, how to avoid overages | AWS re:Post
Billings in free tier | AWS re:Post
I have a 3 $ bill even after using only free Tier resources | AWS re:Post
Community | AWS Cloud Account Fundamentals: Five Essential Best Practices for Managing Cloud Cost

Yes, charges can still happen even under the Free Tier. Here are extra steps to avoid surprises with ECS on EC2:

• Set CloudWatch log retention to fewer days to reduce costs.
• Delete unused ALBs/NLBs instead of leaving them idle.
• Remove unattached EBS volumes after stopping tasks or instances.
• Release unused Elastic IPs.
• Keep ECS services in the same AZ to avoid cross-AZ data transfer costs.
• Check all regions for forgotten resources using EC2 Global View.
• Tag resources to track costs clearly.
• Implement stop/start schedules for ECS services during non-office hours to save costs. Tools like Zopnight from zop.dev can help automate this and put resources to sleep when not needed.

These steps help avoid hidden costs beyond the Free Tier limits.