This lower-interest alternative to a credit card splits up purchases into equal payments over time, but it has downsides.

In fact, a recent study done by Morning Consult found that 17% of U.S. adults used a 'buy now, pay later' loan in the month of June. Affirm is one such popular 'buy now, pay later' option.

"It's crucial to do your research and understand the specific service before using it," Kumar says. A BNPL service like ...