As long as you have a Plan B in place in case things go wrong.
Yes, you will save some money, but you will also be there 3x as long.
You may have 1-2 different students working on your hair at the same time and they may get hair dye all over your clothes (happened to me!) so wear something old. Also, if they mess up the color, you can try to get it re-done for free, but you most likely will have to pony up for the cost of another bottle of hair dye.
For highlights that you want to look nice, I wouldn't risk it. Or if you have a special event coming up, I wouldn't take the chance.
But if you do not have anywhere to go for the next few days, then sure...Why not? I would take the chance...