Hi! Congrats on your anniversary!
If you're interested in pin trading, go to officialdisneypintrading.com They have all the rules on their site. You can buy pin starter kits at the parks or Downtown Disney, with a lanyard and a few pins, to start you off, for $30 or so. If you don't want to spend so much, go to the Orlando Premium Outlets on the other side of I-4 from Disney at the Lake Buena Vista exit. They have a Disney outlet that sometimes carries tradeable pins for less money than buying pins in the parks.
Many people wear their pin lanyards around the parks--but if you really like your pins and don't want to worry about them falling off, invest in locking pin backs. The plastic ones sometimes come off.
Also--if it's your anniversary, make sure to go to Guest Services at all the theme parks--they give out free anniversary buttons for you to wear, and you'll get congratulated all day by the CMs!
Hope this helps you out! Happy Trading!