I think the reason they don't ship less than however many chicks the minimum is, is that they'll get cold in transit: with the numbers they can snuggle up and keep each other warm.
I bought my two pairs of chicks from a local (well, about twenty minutes drive, we don't get feed stores in the CBD
) garden/feed store. Handy place, they let you hand pick your chicks out of the ones they've got, and dispatch you with a bag of chick food which usually lasts until they're ready to move onto pullet pellets or, as we did with the second two, layers' feed
Good question though, I couldn't seem to find anywhere either at first
If there's a group here are BYC from your area (check the Where Am I ,Where are You topic) they might have some, or know a place. There might also be a swap in your area so check that topic, too. Our feed store sells them individually, and I see them on Craigslist often. Good luck.