Yes, the app is free forever for teams with less than 5 developers. For larger teams, there is a 2 week free trial (no credit card required) and the pricing is very reasonable - refer to our pricing page.
Yes, the app is free forever for open source teams - just reach out to us to have your account activated.
No, we do not have access to your code. You can thoroughly review the permissions we have access to when you install our Github App.
No, we can only send messages and can not read your messages. You can thoroughly review the permissions when you install our app for Slack.