Forge is a tool that helps developers easily provision and deploy PHP applications on servers from providers like Digital Ocean, Linode, and AWS. It installs and configures services like Nginx, PHP, MySQL, Redis, and Memcached and allows for push deployment, load balancing, and collaboration features. Forge costs $10/month or $100/year for basic access or $20/month or $140/year for the Plus plan, which offers unlimited servers, sites, and deployments. It is aimed at developers who want an easy way to set up and manage PHP application infrastructure.