I don't know if its legal, but if it is, there will be little shops and carts selling coca leaves. Try it sometime, buy a bag(with lime) and chew it like tobacco then report back! I am very curious about it
I tried the coca leaves when I was in Peru and they didn't do much for me. Made my mouth sort of numb and sick to my stomach.
If you are into the processed version of coca leaves, then you are in for a real treat. Be carefull, I was lucky and was staying with locals.