Birthday Whistles

So someone gave me 4 birthday whistles (blue, red, spotted, and silver) as part of a trade awhile back. I've been trying to find a price for them ever since. According to JN, they're retired and were given out in year 4. Has anyone ever seen them around or sold them? Or am I just gonna throw them in my sdb or gallery for neostalgia (lol) Thanks for any help in advance!