文無しなんだ。

。

I'm broke.

Literal

Penniless [copula-なんだ].

文無し (もんなし) is a colloquial word meaning 'broke' or 'penniless.' なんだ is the casual explanatory copula (な + のだ), conveying 'the situation is that I'm broke.' A very short, natural colloquial utterance.