When you sign up, you'll have access to a sandbox environment where you can can access all features of the paid plans but your apps will only support up to 5 releases. After you upgrade to a paid plan, there is a 30-day money-back guarantee.
All prices are per-application.
Everything in Basic plus ...
Equinox gives free subscriptions to community, personal, or student open source projects. Just send an email to firstname.lastname@example.org with a link to the project.
What kind of open source projects are not eligible for a free license? Any projects developed primarily by for-profit companies will still need to pay for a subscription license. Examples would include docker, influxdb or the heroku toolbelt.