money dumpster

n.
Something or someone you invest your finances in, but in the end doesn't help you at all.

q: Hey, did you use your liberal arts degree to find a good job?
a: No, my education was just a big money dumpster.

q:So are you and Lisa getting married?
a: No, we were never good for each other. In facet, she isn't good for anything... Well... No, she made a good money dumpster.