Hi, I work in a dance studio/gymnastics business in their clothing store in Oklahoma.
Our dance teacher is old school. All the girls have a dress code and a class leotard they are supposed to wear to EVERY practice. If it is class time their hair is up in a bun, they have on their hose, their leo, and the right shoes. They do not ever deviate even if it is a recital rehearsal until dress rehearsal.
It is important for the girls to dress alike because it breaks down social barriers, some have lots of money and some don't. Those that don't have a lot of money look just like those that do, so they are all just kids taking dance class.
Also, the leo's with hose and not wearing other things like tutu's allow the teacher to see the muscles at work during the class, to see if they have their ankles in the right position, if they are using the right position.
Our package for first year girls, itty bitty's, age 3, is a raspberry leo with hose and tan tap shoes, it runs about $69.
Our package for medium level and the advanced girls, is the same leo, hose, tap shoes plus their soft split sole ballet shoes. It runs around $95. Then the enrollment fee for the entire family is $35 and it is due at enrollment. The monthly fee for a one hour class is $50 per month. If they want to do two hours per week it is $84, if they want to do 3 one hour classes per week it is $100 per month and it's $15 more to add each hour. I had, at one time, 4 grandchildren in a total of 7 one hour classes per week and it cost me about $150 per month. It was a couple of years ago and an hour was $45 then. One was in Hip Hop and gymnastics, another was in the combo class, tumbling, and gymnastics, two were in the Buddy and Me" class on weekends.
In gymnastics they are allowed to wear anything they want as long as when they are upside down on the uneven parallel bars their shirt is not showing something they want to keep private or hanging in their way impeding their arms.