JBossAS is the community version - the name has changed to WildFly.
This is free for use in production, but you will have no support for this.
If you use EAP, this is the Enterprise version and you need a subscription to be allowed to use it in production, for development purpose you'll get a 0$ subscription (without support).
If you have a subscription you have Red Hat support for production and development and full access to the knowledge base.
Also you'll receive patches and security updates according to the policy for a longer period.
EAP and JBossAS/WildFly are based on the same sources.