Examples of using "заодно" in a sentence and their english translations:
You're in on it with him!
He's in on it with her.
Since you're going to the supermarket anyway, buy some eggs at the same time.
Be a pal and go out for some bread. At the same time, take out the trash.
Take the newspapers and bring them to Tom. While you're at it, ask when he'll be having lunch.