Yes, both Zendesk Support and Relay offer a Free Trial.
Zendesk Support is designed for Large Enterprises, Medium Business and Small Business.
Relay is designed for Large Enterprises, Small Business, Medium Business and Individuals.
Pricing for Zendesk Support Starts at $19/user/month when yearly whereas for Relay Starts at $9/month when yearly.
Some top alternatives to Zendesk Support includes Zoho Desk, ManageEngine ServiceDesk Plus, Deskero, Support Hub, HelpDesk, Desky, Help Scout, Salesforce Service Cloud, ReadyDesk, Sitehelpdesk, HESK and BoldDesk.
Some top alternatives to Relay includes and NinjaOne (NinjaRMM).