Yes, both Slack and Uptrends offer a Free Trial.
Slack is designed for Freelancers, Large Enterprises, Medium Business and Small Business.
Uptrends is designed for Large Enterprises, Medium Business and Small Business.
Pricing for Slack Starts at $2.67/Month whereas for Uptrends Starts at $15.47/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 Uptrends includes Freshping, Uptime, DevMonitor.io, Monitis, SolarWinds Pingdom, Visualping, pingnow.io, Epic Ping, PingPing and Pingt.io.