Alot of manufacturers enforce what they call 'Minimum Advertised Price' (MAP). They don't allow dealers/stores to advertise prices lower than than MAP. That is why at alot of online stores you have to put the item in your shopping cart before you can see the real price. They can sell it for whatever price they want, they just can't advertise the lower price in some instances.
I think the reason they do it is because alot of people equate price with quallity and they don't want to be perceived as low quality if the advertised price is much lower than their msrp. MSRP is usually higher than MAP.