Once you make it to the dizzy heights of an airline career, you will find that if engaged on airline-related work, but not actually having to be in uniform, (your yearly groundschool session, or SEP) standard dress is typically smart casual (which is chinos, a shirt, and a jumper - no tie). Jeans & t-shirts are generally avoided.
I would say the CTC day should be smart casual as well.
The only time pilots wear suits are for interviews.
I would avoid having to pay upfront fees for any school. Just look at what happened to the Cabair folks.