The concept

An order bump is a complementary offer presented within the checkout itself, before the main purchase is finalized, usually as a simple checkbox that adds a second item to the order without requiring a new payment screen.

Unlike the upsell, which appears after the purchase is approved, the order bump is decided at the same moment as the original purchase, and because of that it tends to have a higher acceptance rate.

How it shows up in practice

At your Nutra checkout, right above the final pay button, a checkbox appears: include another cheaper product in the same order. The buyer hasn't paid the main purchase yet, but they're already there filling in data, already have the intent to spend. Adding another item at that moment is much easier than asking them to come back later and buy separately.

Every customer who comes in through a small offer can climb the entire value ladder. The first order is not where the money is, it is where the relationship starts.

Russell Brunson Source: the Value Ladder concept, in DotCom Secrets. Paraphrased by the editorial team.

The acceptance rate for order bumps is higher than for upsells because it appears before the final approval. The buyer is still in a buying decision state, needs no new convincing, just an additional option that makes the order more complete.