a word/phrase for 贪小便宜的 Need a word to describe someone who doesn't need the product but buys it because he/she has a coupon.

I would use 贪小便宜的 , but what is a proper equivalent in English

Have seen the posts
https://english.stackexchange.com/questions/308698/a-word-for-a-person-who-never-overpays, still couldn't decide which is the best one.

Note：I am looking for the English equivalent of 贪小便宜的，rather than a Chinese synonym.
You can use 葛朗台, which is actually the Chinese translation of the main character's name in Eugénie Grandet, a novel by French author Honoré de Balzac. 

A less witty one would be 小气鬼，which is equivalent to the English penny-pincher or cheapskate.