Semi-Postals are a "charity stamp" that adds an extra charge to benefit a non-postal cause. The Scouting Movement in the beginning and today has greatly benefited by the issue of these stamps by countries.
A semi-postal stamp has 2 values associated with it; the first value is the postal value of the stamp. The second value is the amount to be given to the charity/project for which the stamp was issued. The values are typically represented on stamps as: 32 +8. The cost of such a stamp is 40 cents, where 32 cents can be used for postage and 8 cents will be donated. (Exception: The US Breast Cancer semi-postal fee was invisible - the stamp did not indicate the combined sum of postage and contribution).