I think it all depends on how you view it.  A university names the new
library or gym after the person who provided the funds to build it.  This is
usually viewed as a valid means of honoring and thanking the contributor,
rather than an outright cash purchase of notoriety.  The idea of naming a
species after someone in return for cash could likewise be viewed as the
outright purchase of a taxon, which sounds a bit tacky, though not overly
horrific from my point of view (after all, there are thousands of new ones
available every year).  Or - it could be viewed as justly honoring a person
who has made a significant contribution to research by way of financial
support.  In any case, I believe the astronomers beat the biologists to it
on this one.  I recall reading, some years ago - I don't remember where - of
the possibility of having a star named after you, in return for a sizeable
monetary contribution.
Paul M.