Yes, both ProductPlan and Trello offer a Free Trial.
ProductPlan is designed for Large Enterprises, Medium Business and Small Business.
Trello is designed for Individuals, Freelancers, Large Enterprises, Medium Business and Small Business.
Pricing for ProductPlan Starts at $39/User/Month when Billed Yearly whereas for Trello Starts at $5/User/Month when Billed Yearly.
Some top alternatives to ProductPlan includes Aha!, Roadmunk, ProdPad, Jira, productboard, Productroad, ProductFlare, Next Please, IdeaPlan and LaunchNotes.
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.