Temporary highlights

This summer is the first time I am going to highlight my hair. I want a die that will only last about 4-6 weeks.

My school also does not allow highlights and I do not want to die my hair back to it's original color before school starts up again.

My mom also will not allow me to get it done at a salon. Do you know if there is a product out there that only lasts about 4-6 weeks? If so where can I get it?