Is it fare that travel offer prices in a shop window are not real?

Hi,all I just want to know is there any legal rights or something could be done with few travel agent company's that offering CHEAP holidays and they hang this offer on the shop window, and when you come to query about it they say sorry it's gone. Once I have seen when they hang new offer and i went to check it after 2 min , and again they said its gone. This happen all the times. Are this kind of misleading messages legal. Because looks like they just want to get customer in to the shop and then hope that they will hook up on something else.

I been trying to get these offers of the window since last month , but all end up with sorry they gone or full. Is there any legal action to this behavior.

I know that normal shops with the food or other items which are priced should be sold as the price shown. In event of mistake if the price is lower then should be they must sell it anyway , not causing troubles for the customer of they fault.

The Travel company I'm talking about call Tera travel. Based in N. Ireland Craigavon.

Maybe is someone else who has experience like this.