there is a baseline pigmentation that is inherent to your skin.. we can try reaching that... going WHITE would not be possible.. COST depends on the cause and the treatment needed. There are multiple causes for hyperpigmentation. Sun tan, overweight, pigmentation disorders like acanthosis nigricans or melasma, lichen planus pigmentosus, rhiel's melasnosis, nutritional deficiency, hormonal abnormality, etc are some conditions. The patches of pigmentation need to be examined and assessed to know the cause. Treating it without knowing the underlying cause will offer incomplete and temporary relief; also it will keep rebounding. You should send me images through private online consult for a better assessment of the problem and approaching it accordingly. Hope this is helpful.