Yes, both HourStack and Time Doctor offer a Free Trial.
HourStack is designed for Medium Business and Small Business.
Time Doctor is designed for Large Enterprises, Medium Business and Small Business.
Pricing for HourStack Starts at $9/Month when Billed Yearly whereas for Time Doctor Starts at $7/Month.
Some top alternatives to HourStack includes TimeCamp, TrackingTime, TimeTrack, Busy, Timebase, TeamTime, Sunsama, Tack, Timet and TimeTackle.
Some top alternatives to Time Doctor includes clockodo, TMetric, Toggl Track, Hubstaff, TrackingTime, Clockify, TimeTrack, Timesheet, AtTrack and Time Tracker by eBillity.