From Samuel R. Delany's On Writing --
“One way or the other, directly or indirectly, good fiction tends to be about money.”
“Whether directly or indirectly, most fiction is about the effects of having it or not having it, the tensions caused between people used to having more of it or less of it, or even, sometimes, the money it takes to write the fiction itself, if not to live it. Supremely, it's about the delusions the having it or the not having of it force us to assume in order to go on. Like Robert Graves's famous and equally true statement about poetry, however ('All true poetry is about love, death, or the changing of the seasons'), the generality ends up undercutting its interest.”
Larkin's “Money” probably is about death and the changing of the seasons... whereas Martin Amis's Money is pretty much about the effects of and tensions caused by money. Of course, Delany stresses that there's an equally important sense in which both fiction and poetry can be about anything... even so, I think there's a clue here about what the part of the brain that does fiction also does... what the part of the brain that does poetry also does...
The money poem about money Matt Borondy likes most will will an autographed copy of Katy Lederer's “The Heaven-Sent Leaf.”