Yes, both Slack and Jell offer a Free Trial.
Slack is designed for Freelancers, Large Enterprises, Medium Business and Small Business.
Jell is designed for Large Enterprises, Medium Business and Small Business.
Pricing for Slack Starts at $2.67/Month whereas for Jell Starts at $4/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 Jell includes Synergita, Ally, Weekdone, OKRs.app, Ahundred, Steer, Workboard, SugarOKR, Peoplebox, JOP and SmartOKR.