This trick I learned few days ago from one my clients. While it's very simple to implement, I wasn't aware of this capability of Google Apps and I am sure it can help others as well.
Sometimes, you'd like to setup an auto-forward of incoming emails to some particular email address to be redirected to another external account. It can be an subcontractor which wants to present your company's email address but actually wants to read it from his own email account or any other similar use-case.
The "standard" way of setting it up is to create a Google Apps user account ($50/user/year) and configure Forwarding from the User's settings (Gear button). However, it requires license, knowing the end-user's password and some tedious process of sending confirmation email and approving it.
The much more convenient (each cheaper) option is to do this nice trick:
Step 1 - Create a Google Apps Group
Create a Google Apps group with email address you'd like, like "email@example.com"
Step 2 - Add a member
Add a member with the real, external address to whom you'd like emails to be sent like firstname.lastname@example.org to be delivered (email@example.com in my example).
Step 3 - Verify Group Settings
That's it. From this moment and on, all emails sent to firstname.lastname@example.org will be automatically redirected to email@example.com and you've just saved $50/user/year :)