How Shopify app billing and usage charges work (spend caps included)
Win-back tooling bills in two currencies — a monthly subscription and per-card usage — and Shopify referees both more strictly than most merchants realize. Three mechanisms cover everything; know them and any pricing page becomes ten seconds of arithmetic.
The three mechanisms
- Subscriptions — flat monthly fees, started only by an approval screen Shopify itself renders, billed on your Shopify invoice. No app can invent or raise one silently.
- Usage charges — per-piece fees (here, per win-back postcard) recorded as they happen, settled on the same invoice. Pay-for-what-you-use, with receipts.
- The capped amount — the usage ceiling you approved up front. At the cap, Shopify refuses further charges outright. The runaway-bill story is structurally impossible.
What a well-built win-back app adds
Platform rules prevent unauthorized charges; good apps also prevent authorized-but-unwanted ones: an in-app monthly spend cap checked before each card, an LTV threshold so cards only chase customers worth the stamp, and cancel windows so a customer who returns mid-ladder kills their queued card unprinted and unbilled. Email rungs stay free and unmetered — only paper costs money, and only inside your limits.
Compute your month before it happens
Four numbers decide real cost: monthly fee, per-card rate, included volume, and your expected card volume (your lapsed pool above the LTV bar, not your whole customer list). Here’s the math live with Forwarding Address’s actual plans:
Plan cost calculator
Total monthly cost: subscription plus cards beyond the included volume, printing and postage included. Every plan caps against a spend limit you set yourself.
Below the crossover, free Starter is genuinely the right answer — win-back emails are unlimited there and each card is simple pass-through. The paid tiers earn their fee through included cards and the features around them. One honest month of your own lapse data plus this calculator beats any pricing-page persuasion.
The other half of trust
Billing rules govern what an app may charge you; contact rules govern what it may send the customers you’ve lost touch with — and win-back walks that line more than any other marketing. Who you may actually contact, by channel is the companion guide.
Common questions
›Will win-back charges show up on a separate bill?
No — everything lands as line items on your regular Shopify invoice: the subscription (if any) and each per-card usage charge. One bill, one place to audit, and uninstalling stops billing with the cycle.
›A big cohort of customers lapsed at once — can that explode my bill?
Not past your ceilings. Shopify refuses usage charges beyond the capped amount you approved, and the app’s own spend cap sits below that, checked before every card. A heavy lapse month exhausts the budget and stops mailing — it cannot surprise you on the invoice.
›Why approve a $0 plan at all?
The approval is what authorizes pay-per-card billing to exist. Approving free Starter with its usage ceiling is the merchant-protective version of a card on file: no approval, no possible charge, and the ceiling is chosen by you.