This evening, I had the unfortunate luck of someone completely taking out my wooden mailbox with their side-view mirror, leaving only the post. It was a total accident, and he was quite apologetic, and I had my mailbox back up in about an hour with the help of some 1 1/4" brads.
The mailbox is now firmly reassembled - the only trouble is that he knocked it hard enough that the post is now wobbly! I'm not sure how deeply it's sunk in the ground, and from the way it wobbles, I'm pretty sure it's just a ~4"x4" wooden post sunk into the dirt. What is the best way (where best in this case means quickest and cheapest, without being slipshod) to firmly fix that post in place?