When you take out a loan, you pay the lender to give you the use of that money. What you pay is called interest, and you’ll pay this back in addition to the amount you’ve borrowed.
Interest is usually worked out as a percentage of your outstanding debt, and is paid every year or every month. So the more you borrow, and the longer you borrow it for, the more you’ll pay overall.
Regardless of the type of loan you take out, you’ll see the interest rate quoted as the Annual Percentage Rate (APR). This makes it easy to compare different loans by seeing how much you’ll be expected to pay back on top of the amount you borrow.