Yes, both Trello and Assembla offer a Free Trial.
Trello is designed for Individuals, Freelancers, Large Enterprises, Medium Business and Small Business.
Assembla is designed for Large Enterprises, Medium Business and Small Business.
Pricing for Trello Starts at $5/User/Month when Billed Yearly whereas for Assembla Starts at $9.16/User/Month.
Some top alternatives to Trello includes Quickbase , Smartsheet, ClickUp, Zoho Projects, Freshbooks, Jira, Basecamp, Wrike, monday.com, Asana, Teamwork, ProjectManager.com, Microsoft Project, Worksuite, Trackboard, Quick Base, Todoist, Resource Guru and Height.
Some top alternatives to Assembla includes Quickbase , Smartsheet, ClickUp, Zoho Projects, Jira, Wrike, TeamGantt, GitScrum, Teamwork, ProjectManager.com, Backlog, Axosoft, TaskBranch, Quick Base, Project.co and Height.