Many of these rates (before taxes, might I add) haven’t changed in 20 years. $100-$250 in 1994 aint the same as in 2014. This is why Comic Book Conventions for many comic illustrators, in many cases, are the lifeblood of their comic making (commissions, direct fan interaction books sales).
Support your local mainstream or indie comic artist!!!!
Source: http://www.ehow.com/info_8068093_much-artist-make-per-project.html