Yes, both Slack and Crowdcast offer a Free Trial.
Slack is designed for Freelancers, Large Enterprises, Medium Business and Small Business.
Crowdcast is designed for Individuals, Large Enterprises, Medium Business and Small Business.
Pricing for Slack Starts at $2.67/Month whereas for Crowdcast Starts at $20/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 Crowdcast includes Livestorm, Vimeo Livestream, StreamYard, Zealous, Zoom Video Webinar, Streamster, Stream Club, Streann Studio, YouStreamer and Zuddl Studio.