Yes, both Slack and Workable offer a Free Trial.
Slack is designed for Freelancers, Large Enterprises, Medium Business and Small Business.
Workable is designed for Large Enterprises, Medium Business and Small Business.
Pricing for Slack Starts at $2.67/Month whereas for Workable Starts at $249/month when monthly.
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 Workable includes BambooHR, Pinpoint and Greenhouse.