Let’s say I have a Best Buy credit card, and it has a promotion where spending $1000 in a single transaction gets you 24 months 0% APR financing. If I pay off that balance within 24 months, there should be no interest.
But what if that single transaction actually consisted of several items, and I returned most of them? If, say, the only item I decide to keep is $100 and the other $900 gets returned, what happens?
Do I now have 24 months to pay off $100? Does the promotional balance get nullified and I immediately start accruing interest on the $100? Something else?
Each card from each issuer can be different in the niggling details. You’d have to read the fine print for the specific card you’re talking about to know for sure. All else is commentary about generalities.
Decent bet that if you return enough stuff that the remaining balance doesn’t meet the promotional rate minimum, you’ll lose that rate. As a rule of thumb, if there’s any possible way the promotion can be scammed, somebody has already tried that. Then the lawyers promptly updated the deal to prevent that scam in the future.
Once in a while a company or their promotion department is mind-numbingly stupid, but in general if there’s a trick, they’ve thought of it and precluded it as LSLguy states.
My late wife was a banking attorney at the time the “cash advance” promotions were invented by the credit card companies. Each and every bank had to learn the hard way what terms to include in their offerings to not be scammed alive.
You’d think somebody would publish something in an industry trade mag. Nope. IMO everyone was too embarrassed to fess up to how they got diddled. And/or were hoping to get competitive advantage by making the other guy(s) learn the hard way.
The terms her customers were putting on their offers were literally being updated every month for well over a year as they homed in what would work for them and still generate enough uptake from their cardholders.
Eventually FTC came up with some advisory guidelines, but that was, unsurprisingly, rather too little and rather too late.