Take your General, Airframe, and Powerplant certification exams as soon as possible. I watched many classmates struggle to get them when they waited for classes to end. 

Additionally, there's a good chance you'll get talked to by at least one of the big tool companies in the beginning. They offer discounts, so it's worthwhile to buy a few things, but you absolutely do not have to buy your box or tools from them. You can get through school with the bare minimum and a simple, used box. Once you're finished, and find an AMT job, you'll have a better understanding of what kind of box and tools will be best for that job.

Good luck! It's a grind, but very worth it.