Yes, both Slack and Helpy offer a Free Trial.
Slack is designed for Freelancers, Large Enterprises, Medium Business and Small Business.
Helpy is designed for Large Enterprises, Medium Business and Small Business.
Pricing for Slack Starts at $2.67/Month whereas for Helpy Starts at $15/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 Helpy includes Zoho Desk, Zendesk Support, ManageEngine ServiceDesk Plus, Freshservice, Freshdesk, ProProfs Help Desk, HelpDesk, Jitbit Helpdesk, Helprace, ReadyDesk, LabiDesk, HESK, Sirportly, Help Desk Premier, Support.cc by 500apps and BoldDesk.