where can i buy uniform shirts for teens?

A school uniform is an outfit—a set of standardized clothes—worn primarily for an educational institution. They are common in primary and secondary schools in many nations. When used, they form the basis of a school's dress code. So better buy their uniforms according to their school's dress code.

If you are looking for a long sleeve shirt then better have this Dickies Girl Juniors' Oxford Long Sleeve Button Down Shirt- School Uniform for $12.99. It has three (3) colors available with sizes from Small to X-Large.

But if you want a short sleeve one then grab this Arizona Short-Sleeve Woven Shirt for $14.99 now. This is a favorite for school uniforms. for it is a staple in classic style with * spread collar; button front and chest pocket. 
You also better check this Uniform White Juniors Camp Sleeve Blouse - S for $12.98. This is a blouse with button closure and front pockets. It is made of 55% Cotton and 45% Polyester.