Yes, both Userback and TestRail offer a Free Trial.
Userback is designed for Individuals, Freelancers, Medium Business and Small Business.
TestRail is designed for Large Enterprises, Medium Business and Small Business.
The starting price of Userback begins at $14/Month when Billed Yearly, while pricing details for TestRail are unavailable.
Some top alternatives to Userback includes Backlogs, Backlog, ReportBugz, Buglog, Usersnap, Ybug, Bug-Track.com, Disbug, Feedback Monkey and Toybox.
Some top alternatives to TestRail includes Jira, ReQtest, Zoho BugTracker, Bug-Track.com, TestCaseLab, Qase, Kualitee, QuAck, Crash Catch and QA touch.