Here is an interesting go with. I'm photographing the back only as it is the most wordy and has some great graphics.

The envelope has some writing on front in crayon and pencil with a little glassine window which, I'm assuming would show the addressee's name.

$4 plus first class postage to the US. My Canadian friends, we can chat. A cursory glance shows postage being at least $12 but probably more.

Thanks for looking.