An inexpensive alternative to lapboards

I was recently wishing that my students had lapboards with a staff printed on them so that I could create some quick formative assessments for my students.  If all students had a lapboard, I could easily check for understanding as I teach new notes, fingerings, scales, etc.  We have been learning the notes of the G string, and I wished I could have students draw the note really quick and show me so I could make sure they were really able to know the note names and fingerings.  I priced lapboards and found them to be quite expensive.  Then I started looking for other options and I found these:

I just got these in the mail from Amazon.com, and I LOVE them!  I have already placed a paper inside of each pocket with a staff.  Students can use the staff side to draw notes, key signatures, music symbols, etc, and they can use the back if we need a blank surface.  Also, I love that I can replace the paper inside to be anything I need it to be for my class...these are way more versatile than lapboards (and way cheaper).  I could place a blank fingering chart inside, or rhythm worksheets...so many possibilities.  Also, the expo marker can be stored inside the pocket, so it will not get lost.

We just used these in class yesterday and my students really enjoyed the activity.  I had them work in groups of two to quiz each other on the new notes we have learned and to take turned drawing them on the staff.  As I circulated around the room, I saw great things happening.  My students were on task, and they were helping each other learn the notes. 

After students worked in their groups, we played a game where I call out a note and students race to be the first person to draw the note and hold it up for me to see.  After a few rounds of this note-race, I began to say words and students had to draw the notes for the word I called out (for example:  faced, baggage, bead, dad, bag).