Yes, both GitHub and Jira Service Desk offer a Free Trial.
GitHub is designed for Freelancers, Large Enterprises, Medium Business and Small Business.
Jira Service Desk is designed for Large Enterprises, Medium Business and Small Business.
Pricing for GitHub Starts at $4/User/Month whereas for Jira Service Desk Starts at $10One-Time Payment.
Some top alternatives to GitHub includes LiveCode, Codeanywhere, Visual Studio IDE, CodeinCloud, GitLive, Microsoft Azure, GitLab, CodeSee and Bitbucket.
Some top alternatives to Jira Service Desk includes Freshservice, ManageEngine ServiceDesk Plus, SolarWinds Service Desk, Mint Service Desk, Symantec ServiceDesk, Freshdesk, HelpDesk, ReadyDesk, Milldesk, HESK, Scopedesk and GLPI.