Each student was required to contribute K50 - K200 depending on their outfit. If they just wore jeans and a t-shirt, they would pay K50. Or if they wore denim cutoffs, a black t-shirt, a red bandanna and black sunglasses, like one of my students, they had to pay more (that ensemble cost him K150).
A good number of students took advantage of the opportunity to wear regular clothes. I saw lots of sideways ball caps, girls with National Wear (dresses and skirts and blouses made out of chitenjes), and sunglasses. One girl even shaved a design into her hair, which is not allowed normally. So they really had fun with it.
There were still quite a few students that wore their uniforms today. Those students were still required to pay K50 though. Failure to pay resulted in those students being sent home. I guess compulsory donations are one way to show commitment to school sports. Not sure how that would go over in America though.