I am sometimes asked if you need a serger to sew clothes. Specifically knit clothes. Knits are the stretchy fabrics that can give you a harder time if you don't know how to use them.
I love using my overlock/serger for sewing with knits. I love that it cuts the edge for me, making it completely clean, without any excess seam allowances. I really appreciate using it when I'm sewing over bulky fabrics that my sewing machine would 'cry' about. I like that it doesn't stretch my knits unless I want it to (there's settings for that). There are so many options available on amazon.
I also notice that whenever I sew a knit fabric with a standard sewing machine, I get puckers. These are normal and easily fixed. Simply press your fabric with a hot iron, or as hot as the fabric will allow. This seems to allow the fabric and thread to shrink back/stretch to the new dimensions that you gave it by sewing. It works like a charm almost every time.