Yes, both PingStack and Uptime offer a Free Trial.
PingStack is designed for Medium Business and Small Business.
Uptime is designed for Large Enterprises, Medium Business and Small Business.
Pricing for PingStack Starts at $9/Month whereas for Uptime Starts at $15/Month when Billed Yearly.
Some top alternatives to PingStack includes Uptime, Uptime Robot, Hyperping, DevMonitor.io, UpTime.onl, CallView 360, SiteUptime, pingnow.io, WatchSumo and Loadping.
Some top alternatives to Uptime includes Uptime Robot, Super Monitoring, Dotcom Monitor, DevMonitor.io, UpTime.onl, Odown, Downtime Monkey, SiteUptime, updown.io and SolarWinds Pingdom.