Flat-rate hides the cost stack behind one number per transaction. Interchange-plus passes through wholesale interchange and only charges a margin on top. Which is cheaper depends on volume and card mix, not opinion.
One percentage and one fixed fee per transaction.
Stripe 2.9% + $0.30; PayPal Advanced 2.89% + $0.49; Square 2.6% in-person Free; Braintree 2.59% + $0.49.
No monthly fee. No negotiation. Predictable.
Pass-through interchange + published or negotiated margin.
Helcim 0.15-0.50% margin published. Adyen, Checkout.com, Stax, Payment Depot, Chase, Elavon, Global Payments, Fiserv all quote-only on the margin.
Usually no monthly fee on published versions; quote-only ones may carry monthly minimums.
Illustrative example, not a real company. $50,000 monthly, $80 average ticket, 625 transactions, typical US debit-weighted mix (interchange anchor 1.65%).
Helcim is ~$400/month cheaper on this profile. The break-even (where flat-rate wins) is around $15-$25K monthly for this mix; below that, the $0.25 vs $0.30 fixed gap is too small to overcome and the model has overhead.
| Feature | Vendor | Model | Published margin |
|---|---|---|---|
| Stripe | Flat-rate | Yes (one rate) | |
| PayPal | Flat-rate | Yes (one rate) | |
| Square | Flat-rate | Yes (per channel) | |
| Braintree | Flat-rate | Yes (one rate) | |
| Helcim | Interchange-plus | Yes (by volume tier) | |
| Adyen | Interchange-plus | No (negotiated) | |
| Checkout.com | Interchange-plus | No (negotiated) | |
| Stax | Subscription | No (tier not published) | |
| Payment Depot | Membership | No (tier not published) | |
| Chase / Elavon / Global / Fiserv | Interchange-plus | No (all quote-only) |