After a long day of downhill skiing, a mug of hot chocolate fits the bill. Or does it fill the bill? Someone has to foot the bill for the not-inexpensive adventure; if it turns out that only one ski lift was open instead of the 10 promised, that person might complain that they were sold a bill of goods. English has lots of bill idioms, but the bills involved are not the same.  

The word bill derives from bulla, which in medieval Latin referred to a seal on a document, such as wax stamped by a signet ring. By extension, bulla came to refer to the official documents secured by such seals. It appeared in English in the 13th century as bull, used exclusively for papal announcements, and in the 14th century as bill, which included a wider range of documents, from personal letters to draft acts of Parliament to (by 1480) invoices that listed the price of each good or service individually. Adding those amounts up was called footing (still a part of accounting lingo today) since the sum was then printed on the bottom, or “foot” of the bill. In the 19th century, footing the bill came to mean taking financial responsibility, especially when the expense was incurred by someone else. 

A bill of goods is simply “an itemized receipt” – but today it’s most frequently encountered in an idiom that means “to deceive, to swindle.” To sell someone a bill of goods originated in the 1920s and describes a situation in which a person pays for items listed on an invoice sight unseen, and then receives either inferior versions or nothing at all. The person was sold the list rather than the actual items – the “goods” they were expecting.