Ask HN: Cloud Based Bug Tracker?

There are only 2 of us in the company, both developers for most of the workday. We use zendesk for customer support, heroku for application hosting, grasshopper for the phone system, launchrock for promotion and godaddy for simple web hosting. My last few companies used Jira for bug tracking but it looks expensive as we are just starting out and it needs care and feeding.

Please, your suggestions on an inexpensive cloud based Bug Tracking solution?