Well depending on what you are sending, there are several answers.
If you are sending a plain 1oz letter, just one USA Stamp (44 cents). Each additional ounce up to 3 would be an extra 17 cents.
If you are sending a big yellow envelope, the base rate on that would be 88 cents.
You may want to consult the USPS website for detailed info based on what you are sending.
just 1 stamp if its within the correct size and weight limit
One.
Ohio is a state, one stamp.
The number of stamps a person needs to mail a letter from Virginia to Hawaii will depending on the size of the package. A person should bring their letter to the post office in their city for the correct postage.
just 1
Just one of the right denomination. 44¢
None, email does not require a stamp.
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.
You only need one first class stamp to mail a letter anywhere in the USA.
One Forever stamp, as long as its no more than one ounce.
2-3 days
only one (first class) stamp needed (up to 13oz)