2
it depends on the stamp then you will know how many stamps you will need
1
$1.32
4
For an envelope that weighs 5 ounces, you would need 5 Forever stamps. Forever stamps are typically for 1-ounce letters, so you would need to use multiple stamps to cover the additional weight.
you would only need one stamp
That will depend on the value of the stamps you have. If you have one cent stamps you will need 190 of them. If you have ten cent stamps you only need 19.
3
this would depend on the weight of the package
3 stamps!
At that weight, it would be classified as a large envelope, and postage would be $2.20 as of 2016.
You would have to use 2 stamps to get a small envelope from Florida to Canada. If you do not want to use stamps, you can take it to the post office and it will cost roughly 72 cents to mail it.