Consumer law is an area of law that broadly deals with marketplace fairness for regular people. So, for example, when a person goes out to buy a product for personal use, consumer laws apply to that purchase. Two of the biggest ticket items that regular people purchase are cars and houses, and as a result there are many laws, on both state and federal levels, that apply to ensure fairness in those types of transactions.
Consumer laws also apply to loans that people take out for personal use; both credit cards ("revolving debt") and loans of fixed amounts ("closed-end credit"). You may not ordinarily think of a loan as a transaction, but it is. A whole sub-specialty of consumer law addresses credit in one way or another - what kind of information has to be disclosed by the lender, how much interest is allowed to be charged, how information can be reported on a person's credit report, and what kinds of practices are allowed when trying to collect a debt.