The Threshold Trap

Your cart totals $34. Shipping is $7. Free shipping kicks in at $50. So you add a $16 item you don't need to "save" $7. You just spent $9 extra — but it feels like you saved money. This is the threshold trap, and it's the most profitable feature on every e-commerce site.

Retailers set these thresholds with data, not guesswork. They calculate the average order value and set the free shipping bar 15-25% above it — high enough to require an extra item, low enough to feel within reach. That small gap is exactly one impulse buy wide.