I've read an article about Chinese culture of "good enough". That many apartments fall apart right after they're built because if you do 80% of the job then that's pretty much considered "done".

Doing it correctly or completely isn't part of the contract.

That was a great article: https://aeon.co/essays/what-chinese-corner-cutting-reveals-a...

I don't know how true it is about China, but I certainly recognized that attitude.

A more apt idiom is "if you pay peanuts, you get monkeys." [0]

[0] https://idioms.thefreedictionary.com/if+you+pay+peanuts%2C+y...

another is "you get what you pay for"

https://en.wiktionary.org/wiki/you_get_what_you_pay_for

Another is "you don't get what you don't pay for."

There are two similar sayings that spring to mind:

一分钱，一分货 which means you get the equivalent in goods of what you pay in price, and

好货不便宜，便宜无好货 which means good products aren't cheap and cheap products aren't good.