Yes, both Salesforce Service Cloud and Zendesk Support offer a Free Trial.
Salesforce Service Cloud is designed for Large Enterprises, Medium Business and Small Business.
Zendesk Support is designed for Large Enterprises, Medium Business and Small Business.
Pricing for Salesforce Service Cloud Starts at $25/user/month when yearly whereas for Zendesk Support Starts at $19/user/month when yearly.
Some top alternatives to Salesforce Service Cloud includes Zendesk Support, Zoho Desk, Tidio Helpdesk, Freshservice, Freshdesk, LiveAgent, HelpDesk, SysAid, Jitbit Helpdesk, HubSpot Service Hub, Help Scout, UseDesk, LabiDesk, AzureDesk, HESK and BoldDesk.
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.