There is no definitive answer to this as every fisher has a personal preference and requirement for spinning reels.
Expensive reels are not necessary if you are a beginner (see the best beginner rods by Zebco here) or novice in angling. On the other hand, if you are a committed angler and a seasoned professional, investing in an expensive reel would be a good idea as they offer more high-end features, greater durability, and superior quality.
Nonetheless, cheaper reels are still very popular and reliable for providing what most anglers require.