What the Guard at the Door Understands About Money That Never Stops Moving

I watch the same doors every shift. Customers walk in, customers walk out, and somewhere in between, a card gets swiped at the terminal by the exit. Most people think that swipe is a single event, money moves from their account to the store's account, done. It isn't. It's a small parade of transactions, each one skimming a little something off the top before the store ever sees its share. Understanding that parade taught me something surprising: Affiliate Marketing and POS Terminals all run on similar logic.

Whether it's a blogger's marketing affiliate link, a supermarket's card reader, they share a few core traits:

Infrastructure does the work, not effort. A clickable link and a terminal all sit quietly until someone else acts; a click, a swipe, a market move and only then does money change hands.

Multiple parties take a cut of a single transaction. No one gets 100% of anything. A sale gets divided among the people and platforms that made the sale possible, whether that's an ad network or a card network.

The value compounds through repetition, not intensity. One affiliate link clicked ten thousand times or one terminal swiped all day. The income comes from volume and time, not from any single burst of effort.

Following the Swipe: Who Gets Paid When a Card Is Used at a Grocery Store

I'm not privy to any retailer's private contracts, and every merchant negotiates its own rates, so think of this as the general anatomy of a card swipe at a large grocery chain, not an exact ledger. When a customer swipes or taps a credit card at checkout, the sale amount doesn't go straight to the store. It passes through several hands first:

The Card Network (Visa, Mastercard, etc.): Sets the rules for the transaction and collects a small assessment fee, typically a fraction of a percent of the sale.
The Issuing Bank: The bank that issued the customer's credit card takes the largest slice, called the interchange fee, usually in the range of roughly 1.5%–2.5% of the transaction. This compensates them for fronting the funds and carrying the fraud/credit risk.
The Payment Processor / Acquiring Bank: The company that operates the POS terminal's connection to the banking network takes a processing fee, which can be a flat fee per transaction plus a small percentage.
The POS/Terminal Provider: If the terminal hardware or software is licensed from a third party rather than owned outright, that vendor may collect a licensing or service fee, sometimes bundled into the processor's cut.
Loyalty/Rewards Partners: Many grocery chains fund their own fuel points or loyalty rewards programs out of their remaining margin, effectively giving a portion of the sale back to the customer as a future incentive rather than a fee to a vendor.
The Retailer: After every one of those cuts, the store keeps what's left, out of which it still has to pay for the goods sold, labor, rent, and overhead.

So on a $100 grocery swipe, it's common for somewhere between $1.50 and $3.00 to disappear before the store counts it as revenue. Split between the card network, the issuing bank, and the processor, roughly in that order of size.

The View from the Door

None of this happens because anyone in that chain is doing active labor at the moment of the swipe. The systems were built once, contracts were signed once, and now the money just flows along the rails that were laid down long before the customer ever walked in. That's the same principle behind an affiliate link earning commissions at 2 a.m. or a dividend landing in an account on a schedule nobody has to remember.

Standing by the door, I don't see a transaction. I see train tracks and multiple people get paid just for the rails existing.