Yes, both Phabricator and GitHub offer a Free Trial.
Phabricator is designed for Medium Business and Small Business.
GitHub is designed for Freelancers, Large Enterprises, Medium Business and Small Business.
Pricing for Phabricator Starts at $20/User/Month whereas for GitHub Starts at $4/User/Month.
Some top alternatives to Phabricator includes Jira, Assembla, Jira Service Desk, GitHub, GitLab, Qualified, AnalyticsVerse, Workvivo, CodeSee, SaaS Forge, GetGit and Bitbucket.
Some top alternatives to GitHub includes LiveCode, Codeanywhere, Visual Studio IDE, CodeinCloud, GitLive, Microsoft Azure, GitLab, CodeSee and Bitbucket.