Spend £30.50 more to save £8.50

“Get 10% off when you spend £30.50 more.” A tidy green progress bar, a celebratory party emoji, and two neat milestones. What it never shows you is the sum.

The arithmetic it declines to do

The basket is at £54.50. The 10% tier unlocks at £85.

You spend £22 more than you otherwise would, in order to “save” £8.50.

And this isn’t a quirk of these particular numbers — it’s structural. Closing a gap of ΔS to reach threshold T at discount rate d only pays if d × T ≥ ΔS. Here that means £8.50 ≥ £30.50, which is false by a factor of nearly four. For a 10% tier, the offer is only neutral once you’re already within 10% of the threshold — a basket of £76.50 or more. At £54.50 you are nowhere near it, and the interface presents this as an opportunity.

The one case where it is a genuine saving: you were going to buy those items anyway. Then the discount is free money. The design’s job is to blur the line between that case and the other one.

The ladder never ends

Look at the top of the screenshot: “Your order qualifies for FREE delivery” — already achieved. A goal met. And instead of a completion state, the bar immediately renders the next target.

That’s the mechanic. There is never a “done.” Clear a tier and a further one appears, so the bar is permanently partly-empty and you are permanently almost-there. It’s the same near-miss psychology as a loyalty card that adds a stamp box when you fill the last one.

The principle

A progress bar should measure your goal, not the seller’s. This one looks like it’s tracking your progress toward something you want. It is tracking your progress toward a target basket value someone else picked. Same visual grammar as a download bar or a fitness ring — borrowed to make a spending target feel like an achievement.

Note the vocabulary too: your order “qualifies.” You aren’t qualifying for anything. You’re being sold to, in the language of prizes.

The honest steelman

Delivery thresholds are not a scam. Shipping has real fixed costs, larger baskets genuinely amortise them, and passing some of that back is legitimate. Volume discounts are ordinary commerce.

The objection is narrower, and it’s about disclosure:

1. The net is never shown. It would take one line — “spend £30.50, save £8.50” — and it is conspicuously absent.
2. The ladder has no completion state, which converts a discount into a treadmill.
3. It’s framed as a reward for something that is, arithmetically, a cost.

The math

2.86B shoppers × 20% × 4 hunts/yr × 150s = ~150 lifetimes / year

Time only — the minutes spent scrolling a catalogue for something, anything, worth £30.50. The money is the bigger harm and this site has no unit for it.

The second case where “difficulty: none” is a lie

Like case 018, the fix is one line of text and will not be shipped, because the omission is the mechanism. Most of this site documents accidents — nobody wanted Finder to say 1970. This is designed, tested, and measured by the people who built it.

Difficulty to fix: none

Show the net. “Spend £30.50 to save £8.50.” One sentence, no redesign, no engineering. The reason it isn’t there is the entire reason the bar works.