The origin of the "Convenience Fee."
Wescotte, of Reddit, enlightens us on this pesky charge.
The original intention was a "tax" to add these new services.
When you pay with credit card the merchant is charged a percent of the sale that the vendor is paying for. Big companies can obviously lobby to have these fines reduced but a mom and pop shop pays like 1-2% on each purchase which adds up quick. American Express isn't widely accepted because it has higher rates.
Obviously today everybody has a web site but in the past it was a convenience for customers to be able to pay online. The companies had to pay for people to build the page, buy/rent the hardware, and support the entire thing. This is expensive so charging people a convenience fee was designed to support these new features without raising prices of existing customers.
Today however most of these fees are bullshit but they did have a purpose at one time.