Lol - you do know why people put insane prices on common cars right?
Cuz when people try to sort the 500,000 commodores/corollas/lasers on carsales, some will inevitably pick "descending by price", and guess which car immediately pops up first? That's publicity for you. Obviously the price is negotiable Some people will just call up to find the real price out of curiosity.
In the case of the commodore seller, though, he may have skipped this thought process judging by his spamming "The Best Calais in the world" a few dozen times.