Value of 1902 Encyclopaedia Britannica?

I have an old set of encyclopedias entitled: "Encyclopaedia Britannica with Revised American Supplement". This is a complete 30-volume set, with a "New American Supplement" (according to the coverpage). On the coverpage, it is also referred to as the "Twentieth Century Edition: Revised, with Large Additions, to January 1, 1901". The copyright is, The Werner Company, 1902. They are in generally good condition, with the text and colorplates in very good condition.

Is there any way of knowing the value of this set? Please reply here.

By Drew W.