Zhè cì lǚxíng zhōng yǒu hěn duō bùbìyào de kāizhī.
There were a lot of unnecessary expenses on this trip.
Tips
grammar
不必要 works as an attributive modifier before nouns: 不必要的麻烦 (unnecessary trouble). For standalone 'you don't need to,' use 不必: 你不必担心 (You don't need to worry).
