Pay-as-you-go (PAYG) is the opposite of a flat subscription. Instead of paying $30 every month no matter what, the customer pays for what they actually use — gigabytes consumed, calls made, units shipped, hours worked. The model has obvious appeal: customers feel they only pay for value received, and merchants capture more revenue from heavy users.
Where pay-as-you-go fits
- Cloud and infrastructure — AWS, Twilio, OpenAI all bill per unit of compute, message, or token. Consumption is genuinely variable and meterable.
- Utilities — Electricity, water, mobile data. The customer's usage is the product.
- B2B SaaS with clear usage signals — Per-seat pricing, per-API-call pricing, per-transaction pricing. Used heavily by Stripe, Segment, Snowflake.
Where it does not fit (most Shopify subscriptions)
Replenishment subscriptions — coffee, vitamins, pet food, skincare — almost never use PAYG. The product is a physical good shipped on a fixed cadence; there is no meter to read between cycles. The closest analog is letting subscribers change frequency or skip, which is flexibility within a fixed-cadence model, not true metered billing.
Some Shopify operators experiment with hybrid setups: a small monthly base fee plus per-unit charges for refills. These exist but they are rare. Most subscription buyers prefer predictable monthly costs they can budget — the surprise of a variable bill is the same friction that drives utility-customer complaints.
Trade-offs to consider
- Pro: Lower entry barrier (light users pay less), revenue scales with customer success, no waste-induced cancellations from over-supply.
- Con: Revenue becomes harder to forecast, customers fear bill shock, and dunning gets messier when monthly amounts vary.
If you are running a Shopify subscription business and considering PAYG, the more practical move is usually tiered pricing or volume discounts — fixed cadences with multiple plan sizes. You keep the predictable revenue without inheriting the variability headaches of true metered billing.