Years ago I would read Caps for Sale to my young boys. These days they are teens and have outgrown picture books, but Caps For Sale is still a part of my life in the form of Se Venden Gorras. I have read this numerous times to my Spanish students because not only is the story timeless but it offers an introduction to different teaching themes.
While Se Venden Gorras is slightly longer than some of the other picture books I recommend it can still be read to beginners. It is great for reviewing colors as the differences in the hats are described in the story. There are also several body parts that are mentioned so this book could be used during a unit on introducing the parts (hand, finger, head, back, feet). It is also a great book to use while introducing prepositions (left, right, up, down) and for more advanced students that have a bit of background in the language "transition words" are used within the text like
There are also a plethora of activities that can be done with the book. Here are a few that can be converted into Spanish...
Stack the Caps - To review the colors and patterns on the hats. Also, it would work well with the transition words.
A Spanish Printable - To use with the book. You will need to scroll down to find it.
Or you could do something like this as a class.
And finally, you can do Simon says in Spanish with the actions in the book!