When describing something that is of little or no value, there are plenty of synonyms for the phrase "not worth". One might use the word "unworthy" to convey this idea, or perhaps "insignificant" or "unimportant". Other options include "trivial", "measly", "paltry", or "negligible". When you're looking for a more direct way to express your belief that something is not worth the effort or investment, you could also use phrases such as "not worth the trouble", "unrewarding", or "fruitless". All of these synonyms will help you get your point across, so take the time to choose the one that best suits your purpose.