Yes, both Twilio Flex and Zoho Desk offer a Free Trial.
Twilio Flex is designed for Large Enterprises and Medium Business.
Zoho Desk is designed for Large Enterprises, Medium Business and Small Business.
Pricing for Twilio Flex Starts at $1/User whereas for Zoho Desk Starts at $7/user/month when yearly.
Some top alternatives to Twilio Flex includes CometChat, CloudTalk, Five9, 3CX, Genesys PureConnect, MSG91, Infobip, Cloudonix, CommPeak, CloudContactAI and Messenger Communication Platform.
Some top alternatives to Zoho Desk includes Zendesk Support, Tidio Helpdesk, ManageEngine ServiceDesk Plus, Jira Service Desk, HelpDesk, SysAid, Desky, ReadyDesk, Sitehelpdesk, Trakdesk, HESK and BoldDesk.