T.S.
You may check with the school. My kids school requests that used, but still usable, uniforms be brought to the school for other students to use. They offer them to the student's families for $1 per piece. It helps the school raise a little bit of money but also helps the families A LOT. If the school doesn't have a program like this it's always a great idea to suggest it.
Also, Walmart and Meijer both sell school uniforms in navy blue and tan. They run between $7 and $12 per piece. Usually they're French Toast brand, but I think there's one other. I always buy my daughter's uniforms there and they do great. The uniforms hold up very well to her active lifestyle and thanks to the adjustable straps on the uniform dresses, they even last through most of her growth spurts througout the year. Both also sell uniform shirts in white, light and dark blue, and sometimes burgandy. (I think it depends on the schools near by because my sister lives in KY and her Meijer and Walmart also carried yellow... which went with a local private school.)