a "non" is a term used for high value pets for worth. it also refers to the four pets it came from, nontag, nonswirl, nonjewel and noncoon.
a non is 100-150 2009 rares or 10-12 mid advents (usually shortened to MA).
for a post explaining terms such as MA, nons as well as worth and abbreviations of some pet names:
here!