One First Class stamp on a

       4 1/8" x 9 1/2" envelope.

*How to send a "SASE" (self-addressed stamped envelope):
1. Write your own address on an envelope where the recipient goes.
2. Either leave the return address blank, or put your address there as well.
3. Place a first-class stamp in the upper right corner.
4. Fold this envelope and include it inside another envelope addressed to the address    above.
5. The outer envelope should also be stamped.
6. When we receive your SASE, we use the inside envelope to return your stickers.