It depends on the point of origin, the weight, the class of the mail, the form of transport used.
typicaly 2 stamps
75 cents.
only one
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.
It depends on the size and weight, but if it's a regular letter, a 44-cent stamp will suffice.
how many forever stamps = .94
what the price to mail letter to
5
No, the postman will ignore it. Go get stamps.
maybe 2 0r 3 stamps
Stamps show that you have paid the money to have the letter delivered.
No, you must use US postage stamps.