This is an idea I just recently had. I hope to go to Disney once a year from now on and I really love the pins but personally its just more clutter for me if I collect them...so
I have 2 kids age 19 months and 3. I will buy them 6 pins each and I will then let them trade all 6 ones they really love. I figure the ones they choose will kind of tell a story when you look back at them. I will take those 6 pins and display them in a shadow box (I think thats what its called) and hang it on their wall with a cheap engraved plate inside telling the name of my child, age and month/yr of trip.
So I figure my 19 month can't do much trading so I'll help her out but let her choose, I figure she'll pick a lot of bears since she loves them especially Pooh. As they get older it will be a way for me and them to remember their childhood and they will get a nice collection that means something to them.