母は時は金なりとよく言っていた。

。

My mother often used to say, 'Time is money.'

Literal

Mother [topic-は] time [topic-は] money is-[classical-なり] [quotative-と] often was-saying

時は金なり is a ことわざ (proverb) — the classical copula なり (= modern である) gives it a proverbial ring. よく言っていた = 'often used to say' — habitual past. The proverb is a calque from Benjamin Franklin's English original.