Yes, both Trello and OpenProject offer a Free Trial.
Trello is designed for Individuals, Freelancers, Large Enterprises, Medium Business and Small Business.
OpenProject is designed for Freelancers, Large Enterprises, Medium Business and Small Business.
The starting price of Trello begins at $5/User/Month when Billed Yearly, while pricing details for OpenProject are unavailable.
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 OpenProject includes Quickbase , Smartsheet, ClickUp, Zoho Projects, Freshbooks, Jira, Wrike, Taiga, Asana, Teamwork, ProjectManager.com, Microsoft Project, Leantime, Worksuite, Quick Base, Resource Guru, Redmine X, Height and RedmineUP.