This 'offer' is available most of the times. Checked the price for a particular price about 2 weeks ago. Following day this offer came, the flight I've checked was more expensive. They put the prices up prior to releasing this so called offer.
These are Worse than the Muppets over at Ryanair, People call this airline Swizzair
It'll be today only next week aswell. Note; prices go up when these offers are on.