pony up

Etymology
Originally often poney. US early 19th century. According to Michael Quinion, probably not from the monetary sense of and instead from Latin "Legem pone mihi Domine viam iustificationum tuarum" (“Teach me, O Lord, the way of thy statutes”) in reference to March 25th, a traditional day of debt settlement. This etymology has been accepted by the American Heritage Dictionary.

Verb

 * 1)  To pay (usually a bill, debt or due).