Yes, both Zendesk Support and Celoxis offer a Free Trial.
Zendesk Support is designed for Large Enterprises, Medium Business and Small Business.
Celoxis is designed for Large Enterprises, Medium Business and Small Business.
Pricing for Zendesk Support Starts at $19/user/month when yearly whereas for Celoxis Starts at $25/month when yearly.
Some top alternatives to Zendesk Support includes Zoho Desk, Tidio Helpdesk, Deskero, Support Hub, HelpDesk, Desky, Help Scout, Salesforce Service Cloud, ReadyDesk, Sitehelpdesk, HESK and BoldDesk.
Some top alternatives to Celoxis includes Quickbase , Smartsheet, ClickUp, Zoho Projects, Jira, Basecamp, Microsoft PPM, Wrike, monday.com, Asana, Teamwork, ProjectManager.com, Microsoft Project, Quick Base, Resource Management by Smartsheet and Height.