I am looking for a website that designs party bracelets. The kind bars
use to validate somone is above or below 21. Or to show proof of a
purchase.  The website must also offer customization.

You can try this place:

http://namebadgeproductions.com/$spindb.query.listall3.nbadge.13.ID~20Wrist~20Bands.keyword.nbadge.google.plastic_wristbands

That works.  Got any other sites?

I'm not one of the Google researchers, just do a search on Plastic
wristbands. There are many sites available that offer the service.

Good luck.