a metered postcard is a postcard that already has the stamp made into the the postcard. there is no need to put an adhesive stamp on it.
It depends on where you are sending it from.
1 cent
99c
32.00
35.00
Place the stamp on the top right corner of the postcard.
As of May 2011 any postcard over 4.25"x6" and less than 6.13 x 11.5" is considered regular First Class and is $0.44
A postcard is $.28.
Get a first class stamp
Yes, you can use a Forever stamp on a postcard, but it's overpaying for postage.
The stamp on a postcard with a barcode should be placed in the top right corner.