Argumentum ad lazarum or appeal to poverty is the formal fallacy of thinking a conclusion is correct because the speaker is poor, or it is incorrect because the speaker is rich. It is named after Lazarus, a beggar in a New Testament parable who receives his reward in the afterlife.
This is popularly exploited as the statement, "Poor, but honest."
The opposite is the argumentum ad crumenam.
Examples
References
Argumentum ad lazarum Wikipedia(Text) CC BY-SA