Final answer:
Accounts payable is considered 'free debt' when it is paid within the specified period because it does not accrue interest during that time, whereas other forms of debt like loans or bonds typically do.
Step-by-step explanation:
The liability that is often referred to as "free debt" because it rarely carries any interest if paid within a specified period of time is Accounts payable. This form of liability arises when a company receives goods or services from another entity and is invoiced for them with the agreement to pay later, usually within an agreed period. If the payment is made within this period, no interest is charged, hence it’s often considered "free" as opposed to other forms of debt like loans or bonds that typically accrue interest over time.