For student teachers wanting to dress professionally yet need to take care
of their new professional clothes, maybe this suggestion is too passe, but...
To keep your clothes looking good, you just need to find a funky smock and
wear it. Denim aprons seem to be the HS kid cover-up of choice. I have worn
lab coats and jackets. Currently my childrens' orthodontist saves the older
denim snap-front jackets his staff wears for me. They might have a spot or
a frayed edge or two, but they make great smocks.
I have one in light denim and also a yellow apron that are all covered with
paint - a sort of Pollock-like look that I painted on. Maybe some sort of
junk store retro-look would work or even a plastic chemistry apron? Find
something and make it your signature. Have the kids sign it when you leave.