In most of the finer clothing stores, the clothing is lined, french seamed, or have binding (hong-kong finish) on the seams, so a serger is not a necessity. Designer clothing has these finishes and people pay for the luxury. Nothing is compared to a jacket that is taken off and has a nice finish for other to see weather it is complimentary or coordinated material on a lined or hong- kong finish. Skirts, bodices, dresses with a lining protects the outer fabric from body oils, lotions, and sweat that can ruin and break down finer fabric.
If you are sewing decorative for the home a serger is great for rolled edges on many things like napkins, tableclothes, runners. A serger is great for rolled hems with speciality threads on clothing and for sewing knits. You can find one at garage sales, thift shops, repair shops as people love to upgrade their equipment. Differential feed on a serger is great to use. It is a purchase that you can wait to do as your skills improve.