Wallace Stevens said that money is a kind of poetry and poetry is a kind of money. Currency--from the Latin currere, to course or run--is a state of fluidity as sensible in the immediate moment. Cash is only valuable in so far as its purchasing power is active in the immediate moment. Checks, redeemable only through a bank, have no, and are not, currency.
Late in his life, Ezra Pound would receive young poets seeking his mentorship at Rapallo with a single query. He'd show them a paper bill and ask them to tell him as much as they knew about money. Before learning anything about poetry, they ought know something about cash.
Currency is a collective effort and is contained by the claims of a society at any given time. Some words go out of fashion, lose currency, and maybe even get entirely forgotten. Money backed by no faith is no money at all. Florentines had a tendency to write collapsed lyrics of rivers and society ('like a spring, a prince is a fountain unto his people,' etc). Money and language are the underpinning in these kinds of figurations.
Poets, like princes, have a duty to currency in their trade.
It should then be no surprise to find so much of money in poetry. A group of friends in San Francisco put together weekly pod casts that have recently become increasingly topical. A few weeks ago they did a soul mix on the recession. Ive been interested in musical compilations hinging on specific subjects (money, aliens, etc). I responded with some good old American recession music. This is their site: http://crooksandgrannies.blogspot.com/
And here's my mix, which can also be found on their site: Edgar's rag-tag history of American soul recession music.