I put on my new Van-Cafe 15" SA steel rims with
shiny chrome lug nuts--and 205/65-15 Nokian CSs.
$132 each total.  [The Michelin Agilis equivalent
was ~$150.]

These are directional.  So when I rotate, I'll have
to have 2 tires flipped.  $21 to do this.  A sixth
tire and rim would be ~$200, so I can rotate 10 times
before I run up my costs to the sixth.  That's
50,000 miles.  But I'm still thinking about it.
I have until the first rotation to decide.  ;-)

Richard