The simple psychology of "Decoy Pricing"

Behold, an iconic McDonald's Marketing Strategy (credit to @TheCoolestCool ; Ross Simmonds)

"The medium option is a decoy as it looks overpriced in comparison to a small... But the large looks like a deal."

🍔 Small: $5
🍔🍟 Medium: $5.75
🍔🍟🥤 Large: $5.90