I got my groomsmen personalized bottle openers that were in the shape of a credit card. This is the perfect size for a bag tag, but I am sad to report that they were at a minimum $10 a piece. I don't think the club typically spends that much on each tag, but I may be wrong.
I have one of those cards and they are solid!
Something like this in quantities of 300 or more comes out to $2.25 each. KCFDC logo on one side and number on the other. You can also add a background image.