Hi there! Yes, a serger and overlock is the same thing. People use the term interchangeably. To sew, you don’t really need one. I’ve been sewing without one for many years. If you have a sewing machine that can do a zig zag or overcast stitch, you can use this stitch instead. These stitches are great for finishing seams. You have the option of doing these stitches on the edges of your seams after creating a seam. Or if you want to do them all at once, stitch around the individual fabric pieces after you cut them out. This is especially great for fabrics that tend to fray. They may still fray a little but it should cut down the amount of fraying. Plus if you do it after you cut out your fabric pieces, you don’t have to worry about finishing your seams because you’ve already done this part. The overlock machine does this but will give it an even more professional look. They’re a little more affordable now than they used to be but can still be quite pricey so I always add to to my list as a luxury item I strive to get but you can definitely get by without one. If you want to see a quick example of a finished seam, see my tutorial on working with satin.