挣 has two pronunciations: zhèng (to earn: 挣钱) and zhēng (to struggle: 挣扎 zhēngzhá, 挣脱 zhēngtuō). The 'earn money' meaning (zhèng) is more common in daily life.
usage
挣钱 (zhèng qián) is colloquial for 'earn money.' More formal alternatives: 赚钱 (zhuànqián, same meaning) and 收入 (shōurù, income).
