I also have never seen a combo sewing machine/serger. HOWEVER, a lot of lower-end sewing machines are advertised this way. They are just a sewing machine that comes with a "serger attachment". This is not the same as having a serger. Some differences: (1) sergers sew many stitches per minute, sewing machines much slower, (2) I'm pretty sure the serger attachment does not have the capability of cutting the fabric as you sew the way a serger does; it assumes you are just sewing on the edge of the fabric, (3) the sewing machine uses a zigzag stitch on the edge; this is not the same as the different edge-covering stitches made with a serger, (4) most sergers have what's called "differential feed" which allows you to adjust so knitted fabrics do not stretch while you sew; sewing machines do not have this feature.
In short, it's a marketing gimmick. Very few people who get this attachment with a sewing machine ever use it after trying it out, as it just doesn't do much. A serger does a lot more.
Last edited by Prism99; 02-16-2014 at 12:45 PM.