Commission or discount for payment methods OpenCart

This module adds a commission or, conversely, a discount to the order total depending on the selected payment method. The buyer immediately sees the fair final amount, and the store owner manages costs for acquiring, cash on delivery, and other payment terms.

What does the module do?

• Automatically calculates the surcharge/discount when selecting a specific payment method.
• Supports a fixed amount or a percentage of the running total.
• It can work as a commission (plus to the amount) or as a discount (minus).
• Adds a separate line to the "Order Summary" with a clear name: "Payment Fee (Method Name)" or "Payment Discount (Method Name)".

Settings and data it works with

• Selecting a payment method (by payment method code).
• Operation sign: + commission or - discount.
• Calculation type: fixed amount or percentage.
• The size of the value (number).
• Link to tax class (if necessary, charges taxes on the commission/discount amount).
• Rule status and overall sort order in the totals block.

Benefit for the store: you offset payment system fees or encourage favorable payment methods without changing product prices.
The benefit for the buyer: the final price is transparent even at the ordering stage—no surprises after confirmation.

Application examples

1. Add +2% to the Cash on Delivery payment to cover delivery costs.
2. Offer a 3% discount for "Bank Card" to encourage customers to choose online payment.
3. Set a fixed fee of +50 for rare/expensive payment methods.

Recommendation: Place the module in totals so that it is logically calculated after discounts/delivery—this is configured through Sorting in the "Consider in order" section.