。
She worked solely for money.
Literal
She [topic-は] money [for the sake of-のために] [only-のみ] worked.
のみ is the formal/written counterpart to だけ ('only') — both restrict scope to a single item, but のみ feels noticeably stiffer. You'll see it in news writing, contracts, signage, and elevated prose. のために stacks with のみ to give 'for the sake of money only,' an emphatic restriction. The whole sentence has a slight editorializing tinge — the 'solely' is doing moral work, not just descriptive.