There are several alternatives to Heroku for hosting your Node.js app for free:

1. Glitch: A platform for building, testing, and hosting web apps, including backend Node.js apps. It's easy to use, offers a simple interface, and is suitable for small projects.

2. OpenFaaS: An open-source platform for building and deploying serverless functions, including Node.js functions. You can host your functions on a cloud provider or your infrastructure.

3. Zeit Now: A platform for building and deploying web applications, including Node.js backend apps. It offers free hosting for small projects, and paid plans for larger projects.

4. Firebase: A cloud-based platform that provides a backend-as-a-service for web and mobile applications. It offers a free plan with limited resources and paid plans for more demanding projects.

5. Google Cloud Platform (GCP): A cloud-based platform that provides a wide range of services, including hosting for Node.js backend apps. GCP offers a free trial with limited resources, and paid plans for larger projects.

It's important to keep in mind that these free options may have limitations in terms of resources and features, and may not be suitable for large or resource-intensive projects. Consider your requirements and choose a platform that meets your needs.

Thanks for reading...

Happy Coding!