Wèile qián, tā lián guǐ tuī mò de huó dōu kěn gàn.
For money he'll do any thankless grind of a job.
Tips
usage
Mostly appears in the full saying 有钱能使鬼推磨 (with money you can make ghosts push the mill) — roughly "money talks". The short form 鬼推磨 calls up the whole proverb.