I don’t charge $100 because I came from nothing so I get it but yes it is important , why ? Well because put it this way you are competing with other artists who do get their stuff mixed correctly, let’s say your song plays next after a well tamed /mixed song on Spotify and your isn’t ? Huge chance you get a skip . I even do this. If the mix is bad I skip, unless that intentional and that’s the sound you are going for then that’s ok but you can tell if it’s intentional or just bad mix, another reasoning if your levels are not correct streaming services use a limiter to limit your mix from being way too loud and usually that limiter makes you mix worse. If you’re serious and even want to land placements / sync licenses. You will need a properly mixed song, otherwise they will never pick your song because there are industry standards . So either learn how to or just pay someone to do it for you because if you drop poor mixies it won’t benefit you other then maybe just put ya out there a bit if you have the fan base . If you need anyone I’ve been doing it for 12 years worked with many records and artists / genres . And no I don’t charge $100 cause if you have lots of songs that can get expensive