Buy now pay later sales are expected to break a record on Cyber Monday.Business Wire/AP ImagesThanksgiving online spending hit $6.1 billion, driven in part by mobile device purchases.More shoppers are using buy now, pay later, with $993 million in sales using the method expected Cyber Monday.About 80% of those purchases were made on a phone.This year, more shoppers than ever are using buy now, pay later options that let buyers pay for purchases in installments — and more often than not from their cell phones.