Hello and congrats on your upcoming cruise. Trying not to be too jealous
There are many threads here about buying pins from reputable sources. Unfortunately many of the deals on e-bay are for 'scrappers', or unauthorized pins. They are very difficult to tell from the real thing.
On our first WDW trip, we bought the pin 'booster' packs from the shops and used them for trading. They ended up to be a cheaper cost per pin (I think about $5) and we could trade those for the pins we wanted.
The problem is that CM's can only trade for a pin they don't already have on their lanyard. The trick is to find a CM that doesn't have all the boosters! When we found a CM that didn't have one of the pins, we traded them even if it was for a pin we didn't necessarily want to keep. That way when we found another CM we had a pin to trade that they probably didn't have.
If you read some of the e-bay threads you'll find out why this is a better way to go. E-bay is just so risky and we don't want to contribute to the fake pin problem.
You can buy your lanyard anywhere. I got one from e-bay and one from the parks. The one from the parks is better quality.
To get a trade from a CM you just walk up to them and ask to see their pins. Your 6 year old will be able to trade from CM's with any color lanyard or pouch. Adults can't trade with teal/maroon colored because they are meant for children.
