To get autographed cards through the mail, you need two envelopes, two stamps, a paper, and a card or cards.  On your sending envelope, write your address as the sender and the player's address or their team address if they are on an active roster.  On the receiving envelope, you should write your address on the sender and the recipient.  I do this because, if it a return to sender, you will get your cards back. It is always very important to include your self-addressed stamped-envelope, or SASE for short.  If you don't include your SASE, you will probably never see your cards again.

To protect your cards in the envelope, you can either put your cards in a toploader, or you can stick it between the letter and the SASE.  I don't use toploaders anymore because some of the requests that came, were smeared, mainly because the ink was still wet when they put in the toploader.  Also, NEVER ask any of the athletes for any free stuff they have, like batting gloves, bats, game-used baseballs, etc. because it is just rude.  For the letters, always hand-write them, because it seems like a personal letter, unlike some of the people who type thier letter and get the athlete's autograph to sell for a profit.

To get autographed cards from Canada, you need to buy Canadian stamps.  You have to put the Canadian stamp on the send-to envelope, and a regular US stamp on the return envelope.  The Canadian stamp is a 80 cent stamp and can be bought at Canada Post. 

To send baseballs through the mail to get autographed, you need two large bubble envelopes, two 15x11 sized ones are the ones that I use.  For the baseballs, I use Official Major League ones or the old American or National league versions.  For the pens, blue or black colored ones work best.  Don't use a Sharpie because the ink will eventually bleed into the skin of the ball.  I then take it to the post office and let them weigh it going and coming back and then buy the stamp for it.  It is usually $1.95 to and $1.90 back.