Public (free) JIRA for feature requests/bugs on DevsUnleashed hackathon project (that allows anyone to join)?

Is it possible to have a public JIRA for one’s hackathon project that allows anyone to create issues, on the free tier, or with a cap on user costs? (I notice that JIRA cloud charges per user. Is it possible for anonymous hackathon testers to post feature requests, bugs etc., and not be counted as multiple users?)