Yes, both Zendesk Support and Guru offer a Free Trial.
Zendesk Support is designed for Large Enterprises, Medium Business and Small Business.
Guru is designed for Large Enterprises, Medium Business and Small Business.
Pricing for Zendesk Support Starts at $19/user/month when yearly whereas for Guru Starts at $14/User/Month when Billed 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 Guru includes GitBook, Zoho Wiki, KBPublisher, Drupal Wiki, LearnLode Enterprise, TWiki, Wiki Valley, GoGoWorx, HuForce and ProProfs Knowledge Base.