The expression "paying the piper" means you must bear the consequences for your actions or wrongdoings. There are several synonyms for this phrase, including "reaping what you sow" or "getting what's coming to you." Another common phrase is "getting your just deserts," which means receiving a punishment or reward that is deserved. You may also hear people use the phrase "karma is a boomerang," meaning that the negative effects of your actions will come back to you in time. "Settling the score" or "paying the price" are other alternatives for the phrase "paying the piper." Ultimately, all of these expressions convey the idea that your actions have consequences that you must face.