Three companies can each pay you on one purchase: the store loyalty program, a cash-back site, and your credit card. Episode 5 of Rewards, Explained shows the exact order and the traps that void it.
This is Episode 5 of Rewards, Explained, a series that teaches how credit card rewards work, one idea at a time. Episode 4 covered what a travel card's annual fee actually buys.
Buy $100 of pet supplies at PetSmart and pay with a good cash-back card, and you get $2 back.
Do the exact same shopping trip in a slightly different order, and the same $100 can pay you $6 on a normal day. On one recent Wednesday, it paid $29.
Nothing about the purchase changed. What changed is how many companies were paying you for it.
Stacking sounds like a trick. It is actually just three separate businesses, each with its own reason to pay you, all willing to pay on the same purchase. Think of them as three doors you walk through in order, and each door pays you on your way past:
| Layer | Who pays you | Why they pay | On $100 |
|---|---|---|---|
| The store's loyalty program | PetSmart (Treats Rewards) | To keep you shopping there | $2 in store savings |
| The cash-back site | Rakuten | The store pays Rakuten for sending you, and Rakuten shares it | $2 cash (normally) |
| Your credit card | The card company | To keep you using the card | $2 cash |
None of these companies cancels out the others, because each one is paying you for a different thing: your loyalty, your click, and your payment. It is not a glitch. The store wants you coming back, Rakuten gets paid by the store for sending you and shares that fee, and the card company wants you reaching for their card. Each one pays you on purpose.
PetSmart's Treats Rewards program is free to join and pays 10 points per $1 on merchandise and services, and every 1,000 points converts to $2 in savings. That works out to 2% back. One honest caveat: those are savings at PetSmart, not cash. If you shop there regularly anyway, they are as good as cash. If you were never going back, they are worth nothing.
Rakuten's standing rate at PetSmart is 2% cash back, paid by PayPal or check. The Wells Fargo Active Cash Card earns 2% cash back on purchases with a $0 annual fee, which makes it a clean example of the card layer: at a pet store, a flat 2% card usually beats fancy category cards, because pet stores are almost never a bonus category.
So the everyday stack is $2 + $2 + $2 = $6 on a $100 run. Three times what the card alone pays, for about ninety extra seconds of effort.
Cash-back sites run short promotions where a store's rate jumps. On Wednesday, July 29, Rakuten ran PetSmart at 25% cash back for one day. On that day the same $100 trip paid $25 from Rakuten, $2 from the card, and $2 in Treats savings: $29.
You cannot plan your life around one-day promotions. But if you know the stack, you are ready when one lands on a store you already shop at. That is the real lesson: the stack is the machine, and promo days are the machine running hot.
These come straight from the companies' own terms, and each one has cost real people real money:
Stacking is not a loophole and it is not complicated. It is three companies each paying you for something different, and most shoppers only ever collect from one of them. Set it up once per store you actually shop at, and every future trip pays double or triple, with the occasional promo day paying far more.
Next in the series, Episode 6: booking an award flight with points, step by step, with the real fees shown.
Rates verified on the companies' own pages on July 28-29, 2026: PetSmart's Treats Rewards page, Rakuten's PetSmart store page, and our cards database for the Wells Fargo Active Cash Card. Promotional rates like the one-day 25% change without notice.