It depends on the weight and size and if you're sending it from within the US or from outside. If you can't figure it out on your own, go to your local post office and they'll calculate it for you, but for an ordinary letter-size letter weighing less than an ounce, you just need one first-class mail stamp.
It depends on the weight of the letter and the shipping method chosen. For a standard 1 oz letter sent via First-Class Mail, you would need one Forever stamp if you're sending it within the United States. If it's heavier, you may need additional stamps.
A single 45 cent US Postage stamp will do fine.
typicaly 2 stamps
About one liberty stamp :)
75 cents.
1
only one
you need 3 stamps
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.
Maybe just one not really sure
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.
Regular size letter up to 1 oz needs a 42 cents stamp.
One, as long as it is a 44 cent stamp.