MOTM

Actually, walnut plywood is cheaper than solid walnut.  It does 
require additional work to put the edges on.  It is much more stable 
dimensionally and finished exactly like solid walnut.  
In the past the walnut I have purchased came as rough boards about 
1" to 1 1/4" thick.  I had to first cut a straight edge on one side 
of the boards, then the other.  Then I had to plane them down to 
3/4", taking no more than 1/16" off on each pass.  Then its off to 
the joiner to smooth the edges.  
Plywood is much easier.