One checkbox at checkout added $9 to every order

One checkbox at checkout added $9 to every order
No new traffic. No new creative. Just a checkbox.

Weight-loss offer. Added an order bump on the checkout page: a pre-checked $19 "gut-health companion" add-on with a one-line reason it pairs with the main product.

2 weeks, ~900 orders:
— 41% kept the bump
— Added ~$9 to overall AOV across ALL orders
— Refund rate flat

The order bump converts insanely because they've already decided to buy — wallet's out, friction's gone, the hard "yes" is done. You're just adding a small "sure, why not."

Every offer without an order bump is leaving money taped to the checkout button. Go test it.