Yes, both Slack and WebHR offer a Free Trial.
Slack is designed for Freelancers, Large Enterprises, Medium Business and Small Business.
WebHR is designed for Large Enterprises, Medium Business and Small Business.
Pricing for Slack Starts at $2.67/Month whereas for WebHR Starts at $2/User/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 WebHR includes BambooHR, Workable, GoCo, Paychex Flex, Remote.com and Rippling.