Something that cropped up during Psychology class, on the topic of compliance techniques. In particular, the method of 'lowballing' - getting someone to commit to some action and increasing the 'cost' before he or she can perform the behavior. The technique works because one thinks it is easier to rationalize the additional costs or feels obligated or pressured to see it through once the commitment is made. It is the exact same principle used nefariously in 'advance fee' frauds like the Nigerian Scam, or innocuously by some car dealers or in this case, in cheap flights for sale! 

You would most certainly agree, that this is mostly fecking true. And bloody hilarious.