1
general::
Phrase(s): foot the bill (for something)
Fig. to pay for something; to pay for a bill. • My boss took me out for lunch and the company footed the bill. • You paid for dinner last time. Let me foot the bill for lunch today.
McGrawhill's American Idioms And Phrasal Verbs
2
general::
Pay the bill, settle the accounts, as in The bride's father was resigned to footing the bill for the wedding. This expression uses foot in the sense of "add up and put the total at the foot, or bottom, of an account." [Colloquial; early 1800s]
American Heritage Idioms