。
She only had a small amount of money.
Literal
She [topic-は] small-amount [of-の] money [only-しか] was-not-having.
The ~しか~ない pattern forces the verb into negative form to express restrictive 'only.' Unlike だけ, which is neutral, しか carries the nuance of 'nothing more than' or 'merely' — emphasizing how little she had. The negative なかった at the end is grammatically required by しか, not a separate negation. 小額 is an alternate spelling of 少額 (small amount); both are used, though 少額 is more standard in modern writing.