Correos de Mexico

Walked to the post office.
"Necesita estampilla"
Seven pesos fifty
The smallest bill I have is a $100 peso note.
No cambio.
$100 pesos is approximately $7.45 US. It's not like I was even asking them to break a twenty. Sigh.
So we walk to 7-11, the kids get lollipops, I get change.
Back to post office.
Letter mailed.
Win!