The price is for a matched pair.
These transistor pairs are matched using the well-respected Ian Fritz Method.
They are Vbe matched to be within 2mV or less of each other.
These transistors are suitable for the TTSH project, which states:
It’s a good idea to match all the transistor pairs before starting with everything else. You’ll need 9 pairs of matched 2n3904. And 5 pairs of 2n3906.