It is considered a semipostal...."A semi-postal stamp is a stamp issue that has a surcharge above the postage price. This surcharge may be printed on the stamp itself or simply charged at the point of purchase. The funds raised from this surcharge are donated to a charity or cause, usually related to the image on the stamp. For the Breast Cancer Awareness Semipostal, the U.S. Postal Service used the artwork of illustrator, designer and educator Whitney Sherman.
The price of the self-adhesive, non-denominated semipostal stamp will be 55 cents. As a semipostal, it is valid for postage at the First-Class first-ounce letter rate in effect at the time of purchase. Hope this helps!