If the item was listed by a dealer and the item for sale is a current item, in some instances his distribution agreement prevents them from advertise/posting any price other than msrp.
Contact for Price
I don’t know about the rest of you but I use Audiogon for speed and convenience. So when a seller can’t be bothered to list the price of an advertised item but says “Contact for Price”, I can’t be bothered to spend the time calling him on the phone for his sales pitch.