There is no stone inscribed answer to this question and the cost varies with your teeth whitening needs and procedures. Generally going to dentists for whitening your teeth is costly (that is how dentists afford their plush lifestyles) and costs range from few hundred dollars to thousands of dollars. Professional teeth whitening procedures cost anywhere between $300 to more than $1000. This cost varies depending on the kind of dentist office.
The self use over-the-counter teeth whitening kits provide a cheaper way to whiten your teeth ($20-$100), but do not expect results as good as professional teeth whitening.