Every Shopify merchant has installed an app because the pricing page said "Free." It's a reasonable thing to be drawn to, you're already paying for Shopify itself, plus a theme, plus a dozen smaller tools, and "$0/month" reads as one less thing to worry about.
The catch is that "free" and "no cost" aren't always the same sentence. A growing number of apps in the discounts, upsells, and promotions space don't charge a flat monthly fee at all, instead, they take a percentage of the sales that pass through whatever feature they power. No subscription, no invoice, just a cut. It sounds friendlier than a bill. Whether it actually is depends almost entirely on numbers most merchants never run before installing.
What revenue-share pricing actually means
To be fair to apps that work this way, it's worth being precise about what's usually being measured. Most revenue-share apps don't take a cut of your entire store's revenue, that would be a wildly aggressive model and a hard sell even to merchants who don't run the math. What they actually take a percentage of is attributed sales, specifically the orders that went through their feature. A discount badge app might take a cut of orders where its badge or auto-applied code was used. An upsell app might take a cut of the upsell line items it added to the cart. The scope is narrower than "your whole business," but it's still tied directly to your revenue rather than to a flat cost you can predict in advance.
That distinction matters, and it's also exactly why the pricing can feel reasonable at first and expensive later. A small store sees a small number. A growing store sees the same percentage applied to a much bigger number, and the bill grows with it, even though the app itself isn't doing meaningfully more work to earn that larger number.
Picture a store doing $3,000 a month through a discount feature when they installed a "free" app charging 2% of attributed sales. That's $60 a month, genuinely cheaper than most flat-fee alternatives, and a completely reasonable decision at the time. Eighteen months later, after a good growth run, that same feature is touching $40,000 a month in sales during active promotions. The percentage didn't change. The bill did, to $800 a month, for the exact same feature doing the exact same job it did on day one. Nobody decided to start paying $800 a month for a discount badge, the pricing model just arrived there on its own while nobody was checking.
The math that doesn't show up on the pricing page
Let's run actual numbers, using a fairly typical rate in this category, 2% of attributed sales, against a flat fee of $24.99 a month, the kind of price you'd see from a straightforward flat-rate alternative.
| Monthly sales through the feature | 2% revenue share | Flat $24.99 fee |
|---|---|---|
| $500 | $10.00 | $24.99 |
| $1,250 | $25.00 | $24.99 |
| $5,000 | $100.00 | $24.99 |
| $20,000 | $400.00 | $24.99 |
| $50,000 | $1,000.00 | $24.99 |
The crossover point here lands at around $1,250 a month in attributed sales, past that, the percentage costs more than the flat fee, and the gap only widens from there. For a store running an active discount or promotion, $1,250 in a month isn't an ambitious target, it's often a single good week, sometimes a single good day during a sale.
That last part is the real sting. A revenue-share fee scales with success specifically during the moments your store is succeeding the most, which for a promotions or discount app usually means your biggest sale events. Black Friday, a major seasonal markdown, a viral product moment, these are exactly the times your attributed sales spike, and exactly the times your bill spikes right alongside it. The tool is supposed to be helping you capture more revenue during your busiest period. Instead, that's the moment it gets the most expensive to use.
The costs that aren't the percentage itself
The math above is the headline issue, but a few other things compound it that rarely get mentioned on a pricing page.
Misaligned incentives. A flat-fee tool earns its subscription whether you run one promotion a year or fifty. A revenue-share tool earns more the more discounting happens through it. That's not necessarily a sinister design, but it does mean the app's financial interest and your margin's interest aren't pointed in the same direction. You want just enough discounting to move inventory and acquire customers. The pricing model, structurally, prefers more. It shows up in small ways, a default setting nudged toward broader eligibility, a recommended discount depth that's a little steeper than what you'd have chosen on your own, a nudge to "boost results" by widening which products qualify. None of that has to be deliberate to still tilt slightly against your margin over time.
Budgeting you can't actually budget. A flat fee is a line item. You know it in January, you know it in December, you can put it in a spreadsheet and forget about it. A percentage fee is a variable cost that moves with revenue you haven't earned yet, which makes it behave more like a payment processing fee than a software subscription. If you're trying to model gross margin with any precision, an unpredictable line item that's largest exactly when revenue is largest is a genuinely annoying thing to forecast around.
It quietly changes what kind of cost this is. Software subscriptions are usually treated as a fixed operating cost, the same number whether this month was great or terrible. A revenue-share fee behaves like a variable cost of goods sold instead, eating into margin on every order it touches. Most merchants don't reclassify it that way mentally, they keep thinking of it as "the app I pay for," when it's functionally closer to a small, permanent discount on every sale it's attached to.
When revenue-share pricing actually makes sense
It's not a universally bad model, and it would be unfair to frame it that way. A few situations where it genuinely fits:
A brand new store with uncertain volume and a tight budget benefits from paying nothing until something actually sells, that's real risk transferred away from a business that can't yet afford to gamble on a flat fee for a feature that might not even get used.
Services that take on real risk alongside the percentage are a different category entirely. Buy-now-pay-later providers, for example, charge a transaction fee partly because they're carrying default risk on the customer's behalf, not just displaying something on a page. The percentage there is compensating for actual exposure, not just access to a feature.
And for some merchants, the simplicity is worth it even past the breakeven point. If you genuinely don't want to think about pricing tiers and you're comfortable with a variable cost as long as it only shows up when you're making money, that's a legitimate preference, just one worth choosing knowingly rather than defaulting into.
Finding your own breakeven point
You don't need to take anyone's word for whether a specific app is worth it, the math is simple enough to run yourself in a few minutes.
- Find the app's percentage rate and what it's actually calculated against, total store revenue or just attributed sales through its specific feature.
- Pull your average monthly sales through that feature, or your best estimate if you haven't installed it yet.
- Multiply that number by the rate. That's your expected monthly cost under revenue share.
- Compare it to the flat-fee alternative, if one exists in the same category.
- If your attributed sales are likely to grow, and for most stores trying to grow, that's the goal, run the same comparison again at double and triple your current volume, not just where you are today.
That last step is the one most people skip, and it's the one that actually matters, since the whole point of a growing store is that today's numbers aren't the ones you'll be living with in a year.
As a worked example: a 1.5% rate against $8,000 a month in attributed sales comes out to $120. If a flat-fee competitor in the same category charges $30, you're already paying four times more for what is, functionally, the same feature. Run that same 1.5% against a more ambitious but entirely realistic $25,000 a month a year from now, and it's $375, twelve times the flat fee, for an app that hasn't changed at all in what it does.
Where this leaves the pricing decision
None of this means revenue-share apps are a trap, plenty are run honestly and priced fairly for what they do. It just means "free" on a pricing page is a starting point for a calculation, not the end of one. A flat fee that looks like a bigger number on day one is frequently the cheaper option by month six, and it's the only one of the two you can actually plan around in a spreadsheet without a revenue forecast attached.
It's the principle I built Show Discount around for exactly this category: a flat monthly fee, never a cut of what you sell, so the bill on your best month looks identical to the bill on your slowest one.
A few quick answers
Is a percentage-based app always more expensive than a flat fee? Not always, below the breakeven volume it's genuinely cheaper. The risk is assuming that stays true as your store grows, when the math works against you well before most merchants expect.
How do I find out if an app charges this way before installing it? Check the pricing tab on its App Store listing closely, revenue-share plans are required to disclose the percentage and what it's calculated against, it's just often in smaller text than the flashy "Free" headline above it.
What if the app takes credit for sales it didn't really influence? Worth checking the attribution model specifically. Some apps count any order from a customer who ever saw their widget, not just orders that clearly used the specific feature. That's a separate, valid concern from the pricing structure itself, and worth raising directly with support if the numbers ever look off.
Should I switch away from a revenue-share app I'm already using? Run the breakeven math first before assuming the answer is yes. If your attributed sales are still comfortably under the crossover point, switching might cost you more in setup time than it saves. The math is worth checking on a recurring basis though, quarterly is reasonable, since the crossover point has a way of arriving quietly during a growth stretch nobody was specifically watching for.