Yes, both Miro and GitHub offer a Free Trial.
Miro is designed for Large Enterprises, Medium Business and Small Business.
GitHub is designed for Freelancers, Large Enterprises, Medium Business and Small Business.
Pricing for Miro Starts at $8/User/Month when Billed Yearly whereas for GitHub Starts at $4/User/Month.
Some top alternatives to Miro includes Collaboard, Microsoft Whiteboard, WhiteboardFox, Conceptboard, MURAL, Lucidspark, Whimsical, Board, Zoom Whiteboard and Witeboard.
Some top alternatives to GitHub includes LiveCode, Codeanywhere, Visual Studio IDE, CodeinCloud, GitLive, Microsoft Azure, GitLab, CodeSee and Bitbucket.