One, as long as it is a 44 cent stamp.
A whole lot
typicaly 2 stamps
About one liberty stamp :)
75 cents.
1
If it is a regular size letter and weight that is one stamp.
only one
A normal letter requires just one first class stamp to be delivered anywhere within the USA.
One. From USPS web site: "Forever Stamps can be used to mail a one-ounce letter regardless of when the stamps are purchased or used and no matter how prices may change in the future.
One first class stamp will carry a normal letter anywhere in the US.
It depends on the size and weight, but if it's a regular letter, a 44-cent stamp will suffice.
It takes three stamps to send a letter to Norway.