The text is a play on the concept of increasing intelligence (IQ) through a monetary transaction, which is an absurd proposition. It also plays on the guarantee of 'no money back' as a humorous twist, suggesting that any increase, even if minimal, would technically fulfill the promise. However, it does not exploit different meanings of a word or similar-sounding words for a humorous effect.
Send $ 20 and I will double your IQ or no money back