Rehearsal or practice for ballet doesn't usually require full on costuming unless it is a dress rehearsal. Common attire for dancers in class is for girls; a leotard, tights, and your slippers. For guys it can be the same with the addition of shorts as well. Leotards are a one piece body suit that can resemble a bathing suit with or without sleeves. Students attending standard or beginner ballet class will also wear their ballet slippers to dance in. However, En Pointe classes require a dancer to own and wear point shoes. It takes a lot of practice and breaking in to get used to point shoes. Performers often will go through a period of time where their toes are extremely blistered and sore from learning to dance on point.
When it comes to recitals and performances the possibilities are endless and it truly depends on the story being told. It's common to see a flowing or exaggerated skirt on women because it helps to signify their feminine qualities, and can often give the illusion of flying. Costuming is important because ballet is a very movement oriented dance, and the clothing has to be conducive to running, jumping, and it just needs to be flexible.
The vast array of ballet dance wear is available all over the world and on the internet. Whether it's for a performance, practice, or class, there is no doubt when it comes to the shoes that they need to be of quality. Ballet shoes are one of the single most important elements to one's wardrobe. If the shoes are poor quality, then there is a good chance for the dancer to injure themselves or someone else.