Yes, both Desku and Tidio Helpdesk offer a Free Trial.
Desku is designed for Freelancers, Large Enterprises, Medium Business and Small Business.
Tidio Helpdesk is designed for Large Enterprises, Medium Business and Small Business.
Pricing for Desku Starts at $19/User/Month when Billed Yearly whereas for Tidio Helpdesk Starts at $24/month when yearly.
Some top alternatives to Desku includes Zendesk Support, Zoho Desk, Tidio Helpdesk, Freshservice, MessageDesk, Freshdesk, LiveAgent, HelpDesk, SysAid, Jitbit Helpdesk, eStreamDesk, UseDesk, HelpdeskEddy, Desk360, BoldDesk and Alerty.
Some top alternatives to Tidio Helpdesk includes Zendesk Support and Zoho Desk.