The monthly plan is only one cost
A Shopify subscription is easy to see, but it is rarely the largest cost of an ecommerce order. A useful profitability model also includes product cost, fulfillment, payment processing, advertising, returns and recurring apps.
Allocate monthly overhead per order
To compare Shopify with WooCommerce, BigCommerce or a marketplace, divide recurring platform and app costs by expected monthly orders. That converts fixed overhead into a per-order cost that can be combined with variable fees.
Payment setup matters
Payment economics depend on the payment provider, card type, market and Shopify plan. Use the rates that apply to your account rather than assuming one universal percentage.
Judge plans by total economics
A cheaper plan is not automatically the most profitable if a different plan changes payment economics or reduces other operating costs. Compare the total monthly and per-order impact at your actual sales volume.