Yes, both Slack and UVdesk offer a Free Trial.
Slack is designed for Freelancers, Large Enterprises, Medium Business and Small Business.
UVdesk is designed for Individuals, Large Enterprises, Medium Business and Small Business.
Pricing for Slack Starts at $2.67/Month whereas for UVdesk Starts at $16/Month when Billed Yearly.
Some top alternatives to Slack includes Microsoft Teams, Glip, Google Chat, ChatWork, Dialog, Office Chat, imBee, Takle, SPACE Channel and Teamwork Chat.
Some top alternatives to UVdesk includes Zendesk Support, Zoho Desk, Tidio Helpdesk, Freshdesk, Deskero, HelpDesk, osTicket, Desky, EngageBay Helpdesk System, ReadyDesk, Sitehelpdesk, Support.cc by 500apps, EpicPxls and BoldDesk.