Yes, both Slack and Skedda offer a Free Trial.
Slack is designed for Freelancers, Large Enterprises, Medium Business and Small Business.
Skedda is designed for Large Enterprises, Small Business, Medium Business and Freelancers.
The starting price of Slack begins at $2.67/Month, while pricing details for Skedda are unavailable.
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 Skedda includes and MIDAS.