Funny story here. The verbal response to a funny story "(That's) Priceless" is a common coloquialism down here. That CC company has actually tried to sue people who parody their advert, apparantly unaware that parody is perfectly legal, and that the term "Priceless" has been used coloquially since anyone can remember.

Just remember - take the p!ss out of big business - it's not only legal, it's your civic duty!