1930 Scheduler, McEwen Brothers Oil Well Supplies

This is a schedular from 1930. It has never been written in, is leather, and has only one small nick in the leather. It is in great condition.
This contains measurements, a section on "Applications on express rates and charges", adress, memo, and calender sections, and a census of cities for all 50 states for 1910 to 1920 with the percent of change.In the back "cash account" space can be found as well as a calender for 1927 -1930 on the back page, with the calender for 1930 being on the back blue page.

I've never seen something like this before, and though I know who the McEwen Brothers are, and I'd like to know how common they are and what they're valued at.