I happened upon a single, brand new Michelin MXT, 205/70R14, at one of
the local chain retailers last night. They wanted $49 dollars for it,
and it was labeled as a "one of a kind" (duh!)

To the list:

Should I snap this tire up and continue looking for three more
piecemeal? Or should I buy it and hope I can order 3 more from Michelin
via Costco or some other vendor?

I wouldn't want to end up with 1 tire of Brand X and  3 of Brand Y.
People would talk.

Wisdom appreciated in advance, as always.

Dan