Sending abroad?

[TheBiscuitFactory]

Right I might look a bit of an idiot here, but I am wanting to send from the uk abroad, e.g. America and Europe etc, and I am wondering about postage?
Do I put a large stamp on large envelope or more on staps or what?!
I am confused.
Your help is really appreciated. :-)

[VanillaHoney]

Do you mean the stamps when sending from the UK or do you mean the stamps for the SASE?

A large envelope from Germany for example is 3,45€. So this would be what you have to put on a SASE from Germany back to UK... Or you could use IRCs (International Reply Coupons)