This is the cost for a single unit from ST’s own site. Buy 1 million and you get 3.8USD, but you are still not close to the stated cost on their sides. And adding to this you get 20.- USD P&P and Customs and Handling fees.
A single MCU would actually cost me ca 50.- USD if I purchased from here. I think not!
Norway is threatening to start charging MVA on 1st cent for anything imported. It will be a return to the stone age for people like me. It is not the MVA, but the handling fee of 15.- USD they put on everything that will kill electronics import. The did this in Sweden earlier with devostating effect.