Bought as spares so haven't needed to use them yet, but they appear to be legit replacement pins, and Spool3D's willingness to ship via lettermail made ordering these outside of a larger order reasonably cost effective.
BLTouch - Replacement Push Pin
Free shipping in Canada for orders over $140 before tax. (via Canada Post)
Antclabs BLTouch engineered plastic replacement push-pin
Buy an Antclabs BLTouch replacement plastic push pin in Canada without the surprise cost of the exchange rate!
I have the newer Smart version of the sensor and it's a perfect fit. I have no idea if it will work with the Classic version or not though. That said, as fragile as these are, $10 seems to be a lot of money for what it is.