As you know, I've worked a many schools in my day and I always had the best experience ordering from Evolution ID Cards and Systems.

They offer quality products at fair prices, you can see what they offer for student id cards on this page but they offer a lot of other useful products for schools as well.

I've ordered their educational lanyards and some of the standard badge holders and all worked out great. They have ID printers as well if you wanted to save by making them in house.

Hope this helps!