Teardowns › Pricing & paywalls › Zero-price effect

Trello makes the free plan concrete: "Free for up to 10 collaborators"

Trello · Pricing page · Logged-out visitors (USD shown) · trello.com · captured 16 Oct 2026

Honest nudgeZero-price effect Price & attribute framing

Trello Pricing page, captured 16 Oct 2026 — Our capture, 16 Oct 2026, logged out. Numbers match the steps.

Step by step

1
Zero-price effect
The Free plan says "$0 USD · Free for up to 10 collaborators per Workspace".
2
Price & attribute framing
Standard is "$5 USD Per user/month if billed annually ($6 billed monthly)".
3
A top banner pushes AI features "starting at $5 a month. Upgrade now".

Prices quoted in dollars ($), exactly as shown on the page we captured (US-priced). Prices vary by region and change over time.

The psychology

Why it nudges

A concrete free limit (10 collaborators) makes free feel generous and clear. Leading with the annual-billing price, with the monthly price in brackets, frames Standard at its lowest figure. Whether this lifts upgrades for Trello is not public.

● Mixed evidence · More on zero-price effect, with sources →

Context

A board-based project tool with a large free user base.

Honest nudge or dark pattern?

Honest nudge

Honest nudge: both billing prices are visible on the card.

Steal this, honestly

State the free plan's limits in one concrete line.
If you lead with the annual price, show the monthly one in the same sentence, as Trello does.

What to test: Concrete limits vs feature lists on the Free card. Measure sign-ups and later upgrades.

Next: run it on your product

Apply this with your agent

Take the steps above into your own flow. The prompt carries this teardown, the honest-vs-dark line and the steps.

You are helping me apply a behavioural-design pattern ethically.

Pattern: Trello: Trello makes the free plan concrete: "Free for up to 10 collaborators"
Bias: Zero-price effect: 'Free' is treated as more than just a lower price.
Why it nudges: A concrete free limit (10 collaborators) makes free feel generous and clear. Leading with the annual-billing price, with the monthly price in brackets, frames Standard at its lowest figure. Whether this lifts upgrades for Trello is not public.
Our verdict: Honest nudge. Honest nudge: both billing prices are visible on the card.
Source page: https://nudgeswipe.com/examples/trello-free-for-10-collaborators/ (JSON: https://nudgeswipe.com/api/teardowns/trello-free-for-10-collaborators.json)

Rules: say a brand "uses" a tactic, never that it "worked"; outcomes are not public unless the company published them; no invented uplift estimates; flag mixed evidence. Honest nudge = true, visible, easy to reverse, and in the user's interest. Dark pattern = hides costs, fakes scarcity or popularity, shames, or makes leaving harder than joining. Quote company-published results as "X reports", with the source link, and don’t generalise them. Don’t cite retracted or failed-to-replicate studies as support (e.g. Ariely & Wertenbroch 2002). Don’t state study figures unless they’re on this page or in a source you can link. If an idea crosses the line, link the matching deceptive.design pattern.

Tasks:
1. Ask me for my product, the flow (URL or screenshots) and the goal.
2. Audit where this pattern already appears, or could, in that flow.
3. Propose 2-3 ethical experiments: hypothesis, variant copy or UI, primary metric, and a guardrail metric (refunds, complaints, cancellations).
4. Flag every dark-pattern risk and say how to stay on the honest side.

Open in ChatGPT Open in Claude Open in Grok Open in Cursor

ChatGPT, Claude, Grok and Cursor open with the prompt filled in (it is also copied, in case the prefill doesn't load). Gemini and Codex don't support prefilled links, so the prompt is copied and the app opens; paste it in.

Sources

Our capture of trello.com, 16 Oct 2026
Shampanier, Mazar & Ariely (2007), Zero as a special price. doi.org/10.1287/mksc.1060.0254

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