Another pin trader here. Let me warn you, it is ADDICTIVE.
I let my son start a few years ago. I got him a few cheap pins off ebay (just make sure they are not Sedesma, those are sometimes hard to trade). He's not quite to pin Nazi status, but that's only because I won't let him. He'd love to sit out there with the other Nazi's and talk pins all day long.
We've got well over 300 pins now. He wears a minimum of 2 lanyards in the parks, sometimes 3. He trades for what he likes, but he's got a good eye. He usually picks out limited editions.
Me, I love Tink and have 2 lanyards absolutely full, with more pins stored at home.
I never buy pins on release day. As a matter of fact, I rarely pay full price for pins. I buy at the outlets or ebay, then trade in the parks for what we like. But we've seen folks lined up for hours just to get the pins. They are usually at the Little Green Men shop in Tomorrowland and the line stretches from there, around the planter under the Orbitron (or whatever it's called) back around to the stage area. They only let a few people in at a time. And even if you don't want a new pin, you can't get in the shop until later in the day, once they've cleared the line.