Yes, both Salesforce Service Cloud and Zendesk Chat offer a Free Trial.
Salesforce Service Cloud is designed for Large Enterprises, Medium Business and Small Business.
Zendesk Chat is designed for Freelancers, Large Enterprises, Medium Business and Small Business.
Pricing for Salesforce Service Cloud Starts at $25/user/month when yearly whereas for Zendesk Chat Starts at $19/User/Month when Billed 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 Chat includes ZoomInfo Chat, LiveAgent, LiveChat, LiveEngage, Intercom, Comm100 Live Chat, Smartchat, raychat, Freshchat, RingCentral Engage Digital and Let's Connect.