Yes, both Slack and Intruder offer a Free Trial.
Slack is designed for Freelancers, Large Enterprises, Medium Business and Small Business.
Intruder 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 Intruder 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 Intruder includes and undefined.