Serger Vs Sewing Machine [Help] Sewing Machines Parts and Sales in Los Angeles

Hello, To get down to it I got a sewing machine for christmas which has many stitches. I get and understand that it can be used for many things but the reason I wanted one was to particularly make clothing such as sweatshirts, t shirts, and jackets.

Ive come to realize still among the many stitches my sewing machine can do Its can not keep clothing together too well (as far as I know)

The question is should I sell my sewing machine and save up for a serger or should I keep the sewing machine and use that? I really want to make clothes and be able to wear them and make them for my friends if they like them enough.(I also want them to hold for along time, Made to last.)

Thank You!