As of 2016, one standard forever stamp costs 49 cents.
50-450 usd
This was issued in 2006. It has a face value of 39 cents.
25 cents retail
I believe you are referring to the G Make up rate stamp. Issued in 1994 it has a face value of 3 cents.
That will depend a great deal on which 15 cent stamp it is. There have been stamps issued for many decades with that value. Consult a catalog and identify the specific stamp. It will also help you find the value.
Semi-postal stamps are those sold at more than their postal value, with the additional money going to the specified charity. The U.S. Postal Service has issued three semi-postal stamps and all of them are still valid as postage. The Stop Family Violence stamp was retired on December 31, 2006 and its postal value is fixed at 39¢.
There were many of these notes taken to the post office to get a stamp and a first day cancel seal -- they are not rare. In a nice holder, it has a retail value of $3 to $4.
The previous rate was 29 cents and the new rate was 32. The make up stamp has a face value of 3 cents.
The value of a D series stamp can vary based on its specific denomination, condition, and rarity. Generally, D series stamps are part of a specific series issued by a postal authority, and their worth can be assessed based on collectors' demand and market trends. To determine the precise value, it is advisable to consult a stamp catalog or seek an appraisal from a professional stamp dealer.
Yes they can certainly have value. There is going to have a lot more detail to fully identify the post card. Use of a stamp catalog, looking under postal stationary, in the back of the book, to identify the card. It will also provide a general value.
Information printed on stamps varies enormously from country to country and even within some countries. There are two things a postage stamp will have as a minimum based on the IPU requirements: 1) an indication of country of origin - this is most commonly shown by the country name appearing on the stamp but in a few cases it may be indicated some other way. For example British stamps have no country name but incorporate an image of the reigning British monarch into the design of every stamp. 2) a postal value - i.e. a figure indicating the amount of postal credit you have purchased. If there is no postal value, it is quite possible what you have is not a postage stamp at all.