Hello dangleshow86!
Firstly, welcome to Fanmail.biz!

I hope you enjoy it here!
To answer your question, a SASE (or SAE/SSAE) is a
Self
Address
Stamped
Envelope, which means that you basicly send an envelope, with your mailing address written on it, with postage added (from the coutry you are sending to). The celebrity will use it to mail you an autographed photo back.

It is considered polite to pay for postage as
you want something from the celebrity. For example, sending an envelope to a celebrity (from another country than you) with stamps from your own country would be no good - that's why you can add postage from, for example the USA.
When I send a letter to somebody do I have to send an envelope self addressed inside too ?
As I said, you don't
have to but I would definitly recommend it. {thumb2} Remember, you should always make it very easy for the celebrity to reply and sending an envelope with your address already written on it can safe a lot of time and confusion. Also, it is more likely that they will reply if you include a SASE. :razz: Lastly, send a SASE also can also avoid your address being spelled wrong or mistakes that could make it not reach you.
You can read more about self addressed envelopes
here.
If you can't get hold of any stamps from another country, you can also send an
International Reply Coupon (IRC). {thumb2} You can read more about it
here.
I hope this helps you!

If you have any more questions, please feel free to ask!
Good luck collecting & remember to post you feedback here on Fanmail.biz!
Lizanne