eh it's not entirely true re: American schools. They didn't have them when I went to school there, but from reports from friends back there, many schools have moved to a dress code system which is essentially a uniform. Khaki trousers or skirts, and polo shirts of specific colours. For example. (These reports will differ by state and by county, so make of it what you will. More school districts seem to be experimenting with it, anyway)
I went to Catholic school in the US until my second year of high school, and the cost was ridiculous. 50 USD per skirt, for example, because the schools would all have contracts with just one uniform company, and you were required to own precisely the same plaid, pleats done the exact specified way. It was madness, and very expensive. (50 USD in the late 80s/ early 90s btw- who knows how much it costs now!)
I've just purchased most of DS's first lot of uniforms for his reception year in Sept, and it was about a tenner. The school runs regular secondhand sales, and it definitely seems the way forward for certain bits (fleece bobbles, but the trousers and skirts looked practically new. Same with polo shirts and PE tshirts). I think shoes will be out biggest outgoing, if the rumours are correct that they need outdoor shoes, indoor shoes, AND PE shoes.
Looking forward to that.
I did both uniforms and no uniforms in my school career. Uniforms gave us something to 'rebel' against (seem to recall everyone trying to get away with wearing t-shirts under dress shirts, or leggings under skirts). No uniforms meant I had to have a massive wardrobe. As a student, I think I preferred uniforms. All the stuff about pride in school though, I don't get that at all. :) I think at the end of the day, I liked the uniform because I didn't have to worry over what I was wearing or was it trendy enough.