How to build a SaaS with $0

What you can do with this  

• Build APIs . With API Gateway and AWS Lambda, you get 1M free API Gateway calls (first 12 months)
• Scalable Databases. Dynamodb is a fast and highly scalable NoSQL offering from AWS. 
•  User Management (Sign Up, Login with Email and SMS verification). 
• AWS Cognito gives you all the functionality you need to allow users to sign up, login, verify their emails and phones.
• our HTTPs website (S3 + Cloudfront/Netlify + AWS Certificate Manager). You want a static website.

Their free tier is incredibly inclusive and includes; 

• Personal or commercial projects 
• Public or private repositories 
• HTTPS for custom domains 
• Continuous Deployment 
• Form handling 
• Community support 
• Identity service 
• Split Testing 
• Git Gateway