Is it possible to change your hair color and if so how?

No you cant

Yeah, transform into a Super Saiyan. Thought that was obvious...

its possible.

its not possible as far as i know and before someone else says its possible provide some sort of proof

what about buying hair is tht possible as there is a hair slot

As of right now, there is no way to change your hair other than putting on the chichi helm on a female so they look like her(humans only get the hair appearance.).

haha

Technically you can by putting something in the hair slot but, there are only very limited options though e.g. Android 19 hat, Chi Chi helmet, Ox King helmet, Devil Man helmet, Saiyaman helmet and a few others. These are usually rare and expensive (cash shop items).