To have a glimse of AWS free tier usage all cloud services are listed with their free period of usage and limits drawn in usage.

Amazon EC2

12 months free

750 Hours per month

Resizable compute capacity in the Cloud.

 750 hours per month of Linux, RHEL, or SLES t2.micro or t3.micro instance dependent on region

750 hours per month of Windows t2.micro or t3.micro instance dependent on region

 Amazon S3

12 months free

5 GB of standard storage

Secure, durable, and scalable object storage infrastructure.

 5 GB of Standard Storage

20,000 Get Requests

2,000 Put Requests

Amazon RDS

12 months free

 750 Hours per month of db.t2.micro database usage (applicable DB engines)

Managed Relational Database Service for MySQL, PostgreSQL, MariaDB, Oracle BYOL, or SQL Server.

750 Hours per month of db.t2.micro database usage (applicable DB engines)

20 GB of General Purpose (SSD) database storage

20 GB of storage for database backups and DB Snapshots

 Amazon DynamoDB

Always Free

25 GB of storage

Fast and flexible NoSQL database with seamless scalability.

 25 GB of Storage

25 provisioned Write Capacity Units (WCU)

25 provisioned Read Capacity Units (RCU)

Enough to handle up to 200M requests per month.

Amazon SageMaker

2 Months  free trial

Machine learning for every data scientist and developer.

 250 hours per month of ml.t3.medium on Studio notebooks OR 250 hours per month of ml.t2.medium or ml.t3.medium on on-demand notebook instances

 25 hours per month on ml.m5.4xlarge on SageMaker Data Wrangler

 10M write units, 10 M, read units, 25 GB storage per month on SageMaker Feature Store

 50 hours per month of m4.xlarge or m5.xlarge instances on Training

125 hours of m4.xlarge or m5.xlarge instance per month on Inference

 AWS Lambda

Always Free  

1 Million  free requests per month

Compute service that runs your code in response to events and automatically manages the compute resources.

 1,000,000 free requests per month

Up to 3.2 million seconds of compute time per month

 Amazon Lightsail

Free Trial

750 Hours 1 Month Free Trial

Virtual Private Servers made easy! Everything you need to jumpstart your project on AWS with compute, storage, and networking.

 30-days free (750 hours per month)

Try the $3.50 USD Lightsail plan free for one month when using Linux/Unix

Try the $8 USD plan free for one month when using Lightsail for Microsoft Windows Server

Amazon GuardDuty

30 Days Free Trial

Intelligent threat detection and continuous monitoring to protect your AWS accounts and workloads.

Amazon SNS

Always Free

1 Million publishes

Fast, flexible, fully managed push messaging service.

 1,000,000 Publishes

100,000 HTTP/S Deliveries

1,000 Email Deliveries

 

To learn more about Amazon AWS free tier visit   AWS Website