I think all of us started out just buying pins we affectionately call "Keepers".
But the true benefit is not in the pins you trade or get in return, it's the friendships that develop over time. That's why, for example, the Parkhopper Pin Party is such a success. To me, pins are secondary. The friendships are prime. Vince, Suzi, Nat, Ruthie, NJBlackberry, et al. and all the stories like the small bottle of Jack Daniels with a Kungaloosh tag from Germany.