Yes, both Trello and Marker.io offer a Free Trial.
Trello is designed for Individuals, Freelancers, Large Enterprises, Medium Business and Small Business.
Marker.io is designed for Large Enterprises, Medium Business and Small Business.
The starting price of Trello begins at $5/User/Month when Billed Yearly, while pricing details for Marker.io are unavailable.
Some top alternatives to Trello includes Basecamp, Wrike, Smartsheet, Zoho Projects, monday.com, Asana, Teamwork, ProjectManager.com, Microsoft Project, Worksuite, Trackboard and Height.
Some top alternatives to Marker.io includes The Bug Squasher, BugHerd, Buglog, TrackJS, Ybug, BugHost, DebugMe, Bug-Track.com, Disbug and Toybox.