If McDonalds has their BigMac Meal labeled with CHF 12.50 (the current price in Switzerland IIRC) the cashier won't be able to refuse to sell it to me for that price even if I look particularly hungry and it's 4 O'Clock in the morning (and might thus be ready to pay more than 12.50). At least in Switzerland you are generally obliged to honor your displayed prices.
I have never bought a home (I'm a 23 y/o student), and I don't know if the process in the US would be comparable to the process in CH, but if a home is labeled with a price of say CHF 1'250'000 I expect to be able to walk in there with a bag with 1'250 CHF 1000 bills and pay for the house without additional price haggling. However I can imagine that this is not how it works (apart form the "pay with cash" part, which I know works for sure).