As advised, the term is derogatory, usually applied to someone who clearly either has money, or didn;t, but does now, and claims socialist principles.
It's a term I have seen leveled at comedian Ben Elton and musician Eric Clapton.
Personally, I think it's meaningless - having, or obtaining money doesn't mean that your political ideals have to change over night.
Being rich does not bar you from having a social conscience, so the idea that rich people are not entitled to maintain views they formed when they were not rich, is baseless.