Vouchers, Coins and Stackable Discounts: The Margin Math Before You Join a Campaign
Short answer: Not every discount a buyer sees costs you money. Platform coins and platform-funded vouchers are usually paid out of the platform's own promotional budget — but a seller voucher, or a seller-funded slice of a stacked deal, is a real marketing cost that should be modelled the same way you model ad spend, not quietly netted against your GMV. Before joining any voucher or coin campaign, work out which layer of the stack you are actually funding, then check the order still clears COGS and platform fees after that cost.
Order income after voucher = Net Revenue − COGS − seller-funded voucher cost (a marketing cost line, not a GMV adjustment)
What's the difference between a seller voucher and a platform voucher?
A platform voucher or coins discount is typically funded from the platform's own budget as part of a campaign it runs to lift conversion — it does not come out of your payout. A seller voucher is a discount code you configure and fund yourself, deducted from what you actually receive. Stacked promotions during big campaigns often combine both in the same checkout: a platform coin discount, a seller voucher, and sometimes a free-shipping subsidy split between platform and seller.
The trap is treating the whole stacked number — "buyer paid 30% less" — as your cost. Most of that 30% may be platform-funded. Your job is to isolate the seller-funded slice, because that is the only part that hits your P&L.
Do coins cost the seller money?
Usually not directly — coins and cashback are typically platform-funded promotional tools. But some coin or cashback campaigns ask participating sellers to co-fund a portion of the redemption, especially for higher-value or opt-in tiers. Read the campaign terms before you assume a discount line is free; "platform voucher" and "co-funded voucher" can look identical to the buyer while costing you very differently.
Why doesn't a "50% off" banner mean you lose half your margin?
Because most of that headline percentage is usually a blend of platform funding, seller funding, and sometimes a temporary price adjustment on the listing itself. What actually matters for your P&L is only the slice you fund — and, separately, whether the platform reports GMV on the pre-discount or post-discount value, since that changes how the headline number compares to what actually settles. Treat the seller-funded voucher as a cost line, similar to how ad spend and affiliate commission sit below gross profit, rather than trying to back it out of revenue.
Worked example: a seller-funded voucher stack on an RM 100 order
| Line | Amount (RM) |
|---|---|
| Order value (pre-discount) | 100.00 |
| − Platform fees (~18.9%–19.98%, platform-dependent) | ~19.00 |
| − COGS (est. 45% of order value) | 45.00 |
| = Gross profit | ~36.00 |
| − Seller-funded voucher (10% of order value) | 10.00 |
| − Ads cost on this order (est.) | 8.00 |
| = Net profit before other costs | ~18.00 |
On this order, a 10% seller-funded voucher cost about as much as the ad spend that drove the sale — both are real deductions below gross profit, and neither shows up if you only look at GMV. (Figures illustrative; confirm your own COGS, platform fees and ad cost per order.)
How much can a stacked discount campaign actually cost you?
Add every layer you personally fund — seller voucher percentage, any seller-funded coin top-up, and any seller-absorbed shipping subsidy — as one combined percentage of order value. Compare that combined percentage against your gross margin before marketing costs. If the seller-funded stack is close to or bigger than your gross margin, the order is losing money the moment it is placed, no matter how good the GMV looks on a campaign dashboard.
Should you join every voucher or coin campaign?
Not automatically. A useful three-question filter before opting in:
- What percentage of the stack do I actually fund, after separating out platform-funded coins and vouchers?
- Does gross margin on this SKU comfortably cover that percentage, or is it already thin before you add COGS uncertainty and ad cost?
- Is the expected conversion or ranking lift worth the margin given up — campaigns can be worth running at breakeven or a small loss for the right SKU, but that should be a deliberate call, not a surprise you discover in settlement.
High-margin SKUs can usually absorb a deeper voucher stack than thin-margin ones; running the same stack across your whole catalogue without checking SKU-level margin is how a campaign that looked great on GMV quietly loses money. See SKU-level profit for the same trap on a per-product basis, and how to price products across TikTok Shop and Shopee for pricing in a voucher stack up front.
Model it before you commit
The safest way to decide is to model the order with the seller-funded voucher already subtracted, using your real COGS and fee numbers, before the campaign goes live — the profit margin calculator is a fast way to check a single price point. Doing this per SKU, per campaign, reconciled against what actually settles rather than the campaign dashboard's headline discount, is where a spreadsheet stops keeping up. Inseller was built by a seller running real voucher-heavy campaigns on TikTok Shop and Shopee, to show net profit per order and per SKU after every seller-funded cost — including the voucher line most sellers never separate from GMV.