The cost is 5 for just $5 and that includes postage to Canadian postal codes and US zip codes!
These Egg Color Reference Charts are only for referencing the shell color, not grading it.
Frank Decmar, from England, came up with the charts originally for the British Araucana Club and I worked with him to have custom Ameraucana Alliance egg charts printed. I asked him about the letters and numbers associated with the colors around the perimeter and he said...
It was just a numbering system I came up with... Could have been letters around the edge, but it didn't look right! There is no right or wrong- just a way to ID the colour of someone elses hatching eggs when you're not there in person to see what they look like. it was all because I was so fed up with people describing their eggs as amazingly blue, then when they arrived they were clearly much greener than mine! Hope that helps. 
Note the scans of egg charts, below, are not true to color. The contrast has been altered.
