# A/B test: suggest cheap add-ons to reach free shipping

> If the cart suggests two or three inexpensive products that close the gap to free shipping, then average order value will rise, because we give shoppers an easy way to avoid paying for delivery.

- Source: https://bixlow.com/en/ideas/cheap-add-ons-to-reach-threshold
- Language: en
- Updated: 2026-11-02
- Publisher: Bixlow

## Why it can work

Picture someone with €41 in the cart and free shipping from €49. They know they are €8 short. What they do not know is what to buy with that €8 without browsing the whole store again.

Hand it to them (socks, a case, a refill, something they would end up buying anyway) and the decision goes from “let me find something” to “add this”. That is one click.


## How to set it up

In Bixlow you describe the change to the agent, it builds it on your site and launches it as an A/B test once you approve it. A/B tests are on the paid plans, starting with Standard.

1. Pick a short list of cheap, in-stock products that go with almost anything. Somewhere between €3 and €15 is usually enough.
2. In the variant, show two or three of them under the cart total, with their price and a direct add button that keeps the shopper in the cart.
3. Only show them while the cart is below the threshold, and favour the ones that close the gap in one go.
4. The control is your cart as it is. If you already have a “€X to go” bar, keep it in both versions so you measure only the add-ons.


## What to measure

|  | Metric |
| --- | --- |
| Primary metric | Average order value |
| Metric that must not get worse | Orders per visitor |
| Where it is measured | On the order confirmation page |

_If order value goes up but orders drop, the cart has become cluttered and people are leaving._


> **When I would not test it.** If you do not offer free shipping, there is no gap to close. Same if your catalogue has no cheap products that make sense as an extra: throwing in any €5 item just to reach the threshold feels forced, and shoppers notice.


## Other versions worth trying

One product instead of three, the one that closes the gap best. Or the add-ons grouped under a heading that says what they are for: “To get free shipping”.


## FAQ

### Which products should I suggest?

The ones people already add on their own to small orders. Look at your low-value orders and see what repeats. If nothing stands out, try consumables and accessories for your main products.

### Isn't this the same as “customers also bought”?

No. Here the suggestion has a concrete reason for the shopper, skipping the shipping fee, and the price is chosen to close the gap. A generic recommendation does not answer that.

### What if the shopper is already over the threshold?

Then show nothing. The block only makes sense while money is missing; once they are past it, it is clutter.

## Further reading

- [Previous idea: what's left for free shipping](https://bixlow.com/en/ideas/free-shipping-progress-bar)
- [How to write a CRO hypothesis](https://bixlow.com/en/glossary/cro-hypothesis)
- [Sample size calculator](https://bixlow.com/en/tools/sample-size-calculator)