Jordanne Wells estimates that she most likely had near eight bank cards by the point she graduated faculty from Ohio Wesleyan College — and an entire lot of debt.Sadly, on the time, she did not know that carrying a stability on her playing cards was hurting her credit score rating till she went to purchase her first automotive in 2007: a used 2001 Honda Civic EX. It was then that she realized her rating sat within the low 600s.With solely a mean credit score rating and never a lot cash in her pockets, she known as her father in Jamaica to see if he might help.Together with her dad’s assist, she charged the $1,500 down cost onto his bank card and took out a loan to cowl the remainder of the acquisition. However Wells, who immediately runs a private finance weblog for millennial girls known as Sensible Cash Ladies, would not suggest others to observe in her footsteps.Under, CNBC Choose hears from Wells on the 4 classes she realized from utilizing a bank card to assist purchase a automotive.1. It is a ‘double whammy’Wells says charging a down cost for a automotive onto a bank card is a “double whammy.””Not solely do you need to make a cost on a automotive, however now you additionally should make this double-digit curiosity cost on the bank card as nicely,” she says.Whereas Wells took care of paying the automotive funds every month, she additionally felt obligated to assist her dad repay the $1,500 cost on his card. Sadly, the stability racked up excessive curiosity prices since they could not afford to pay all of it off directly.”Except you’ve gotten the cash available to repay [the card] instantly, do not do it,” she says.2. You might be taken benefit ofIn Wells’ expertise, she says automotive dealerships usually make it very easy so that you can use your bank card however do not be fooled by it. “They are going to at all times inform you, ‘No downside, it is not a giant deal,” she says. “However, yeah, having to pay a excessive rate of interest in your bank card is a giant deal.”Having immigrated to the U.S. from Jamaica by herself at 17, Wells additionally wasn’t conscious of the various rates of interest you may be charged. When she was supplied an 11% rate of interest on her automotive loan, she thought that was regular.”I believed that was nice,” Wells says. “Then six months later, I overheard my coworker say that she bought her automotive for 0% curiosity.”3. Your credit score will doubtless take a hitWhen you utilize your bank card to pay for something, you’re including to your credit score utilization charge. The overall rule of thumb is to not use greater than 30% of your credit score restrict, however placing a giant down cost for one thing like a automotive can simply make your utilization charge leap.In the event you do not pay that massive automotive buy off instantly, this greater utilization charge will ding your credit score rating and a decrease credit score rating might imply that you find yourself being charged extra for auto insurance coverage.After all, any cost exercise — whether or not it is in your bank card or your automotive loan — will get factored into your general credit score historical past. In the event you’re ever late on these funds, or worse you miss them solely, your credit score rating will drop.4. Think about using a card with massive rewards (provided that you may pay it off)Wells’ father did not earn any rewards when he charged the down cost onto his bank card, however she factors out that this may be the one situation the place it might make sense — in case you pays the stability off instantly.A few of the greatest bank cards, together with the American Specific® Gold Card, the Chase Sapphire Reserve® and the Capital One® Enterprise® Rewards Credit score Card, have beneficiant sign-up bonus gives that include excessive spending necessities. Charging a giant expense, just like the down cost on a automotive, can assist you simply meet that spending threshold to earn the rewards. However “do not do it until you are paying it off straight away,” Wells says, as a result of the value of the rewards would not offset the extra curiosity prices you will face in case you carry a stability month to month.Details about the Capital One® Enterprise® Rewards Credit score Card has been collected independently by CNBC and has not been reviewed or offered by the issuer of the cardboard previous to publication.Editorial Be aware: Opinions, analyses, critiques or suggestions expressed on this article are these of the CNBC Choose editorial employees’s alone, and haven’t been reviewed, authorised or in any other case endorsed by any third get together.