Yes like what aaron said about the wood cages^
since you teach high school though i would really go for a rack over cages. either build one out of melamine, or buy a plastic one from reptile basics like slim posted above^^
If you have any q's about the melamine feel free to ask or pm me, id be happy to help.
And for the record, i think that its AWESOME you have snakes in your classroom. I wish my bio teacher in highschool had snakes!