That can get to be pretty tricky! For First Class mail you need to use a stamp or combination of stamps that matches the current cost of 41 cents for the first ounce. Depending on what type of mail, businesses can get all sorts of discounts for sorting things, having the nine digit zip code and meeting other requirements.
A quick visit to the USPS web site will give you the current rates and requirements. They also have a page that will show you what the value of the non-denominated stamps.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.