I'm not going to join a new band my band director is creating which would mean said band wouldn't happen
Why wouldn't you want to join the band?
I don't want to spend damn money on instruments or other stuff.
It's understandable not to want to invest time and money into something you don't care much for. Both resources are limited and everyone should be able to do what they wish with it.
If they force me into it anyways I'm going to make a big deal about it and make my band director life hell.
You have your own choices in life so be strong and don't let them choose for you. Just never show up if forced, that way you won't have to resort to being a bad person otherwise.