Yes, both Zoho BugTracker and Userback offer a Free Trial.
Zoho BugTracker is designed for Freelancers, Large Enterprises, Medium Business and Small Business.
Userback is designed for Individuals, Freelancers, Medium Business and Small Business.
The starting price of Userback begins at $14/Month when Billed Yearly, while pricing details for Zoho BugTracker are unavailable.
Some top alternatives to Zoho BugTracker includes Jira, Zoho Projects, FogBugz, The Bug Squasher, Sentry, ReportBugz, zipBoard, BugHost, Bug-Track.com and Disbug.
Some top alternatives to Userback includes Backlogs, Backlog, ReportBugz, Buglog, Usersnap, Ybug, Bug-Track.com, Disbug, Feedback Monkey and Toybox.