Yes, both Slack and SolarWinds Service Desk offer a Free Trial.
Slack is designed for Freelancers, Large Enterprises, Medium Business and Small Business.
SolarWinds Service Desk is designed for Large Enterprises, Medium Business and Small Business.
Pricing for Slack Starts at $2.67/Month whereas for SolarWinds Service Desk Starts at $19/User/Month.
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 SolarWinds Service Desk includes Freshservice, ManageEngine ServiceDesk Plus, Ivanti Service Manager, Jira Service Desk, Symantec ServiceDesk, InvGate Service Desk, IBM Control Desk, HelpDesk, SysAid, Sitehelpdesk, HESK and TechExcel ServiceWise.