You only need one!
TWO US Forever stamps will suffice (USA to London post card)
4
how many forever stamps = .94
7
it cost .26 cents
One 28 cent stamp will do the job if you are mailing your card from within the US.
3 Forever Stamps should work just fine.
It takes at least 2 forever stamps plus 10 cents.
it takes at least 4 forever stamps and about ten regular stamps :d whats in india?? lol
usually none, but if it needs a stamp, just one stamp is needed.
No you cannot use US stamps. Items mailed must have the stamps of the country of origin on them. Most shops will be able to provide you with the appropriate stamps to use to mail with their cards, or visit their post office!
You are not allowed to use the Forever Stamps for international mail. They are for domestic (inside the US) use only.