It's a very common word in Yiddish and can be used in various contexts, like:
* "This is a bilig store." (meaning the store sells cheap things)
* "That car is too bilig for me." (meaning the car is too cheap, maybe not good quality)
* "I bought this shirt bilig." (meaning the shirt was cheap)
There are other ways to say "cheap" in Yiddish depending on the context, but "bilig" is the most common and versatile.