Everyone adores a good deal, but we're well aware that nothing comes without a catch. Still, that doesn't stop us from being drawn to anything labeled "Free" and piqued by what's being offered. 

@WTF Signs, part 35/piximus.net

It's a shrewd marketing tactic that lures in the thrifty shopper, only for them to discover the catch behind the enticing offer. There's a grain of truth in it: once you've paid the price, you technically get it for free... perhaps.