Don't get into it for financial reasons. Do it for fun. I buy and sell, but I only sell off my duplicates that I haven't been able to trade away, or pins I decide I don't want anymore. I buy WAY TOO MANY PINS because it is ADDICTING. There was a solid year straight I bought EVERY pin DisneyShopping produced and
Disneyland put out in multiples. I was on-line every morning when Disney released the pins, and had a friend in Cali at the time who went to the park and got them for me each week. I could afford it that year and was obsessed and wasn't able to trade away many of them, even after all this time, so they go to eBay for much less than what I paid even though pin prices have skyrocketed since then.
My other problem is mystery sets. I am obsessed with them, but won't buy them from eBay. I want sure fire legit sets not at jacked up prices. So, I buy tons of the boxes and my duplicates that I can't trade go to eBay. I only know a few people who collect the mystery sets so we usually trade with each other to try to complete our collections without buying more boxes and pouches.
When trading, I have my show-off lanyard, usually either my Maleficent purple lanyard, or a pirate lanyard. I put medallions on those and use them to attract people to ask questions about pin trading and get them into the hobby

. I usually give away a couple pins to get people started as well. Then I have my trader lanyard. If I see a little kid I'll let them pick anything they want. If an adult wants to trade, then I am open and easy about it because I figure it is my trader lanyard. But, if I suspect a shark I won't trade. When I see something I REALLY want to keep it goes in my pocket or purse so I don't lose it or trade it back accidentally. I'm lucky enough to have a local trade meet that meets monthly and a lot of those people go to the parks much more frequently than I do so it is a lot of fun. When I see kids and teens at the pin racks (or adults for that matter) looking at fancy expensive pins and complaining how expensive they are to just trade away, I usually steer them toward the booster packs or pin with purchase promotions as the most economical pins to trade and tell them buy them if they want to keep them. Lord knows I buy a lot in the parks. But I keep them on the card and bring them home to my pin books. A lot of people don't know the cast members have to trade. A lot are worried that if they don't have a nice pin they won't be able to trade.