If you call Coach customer service in Jacksonville they will send you one for free, but it may take several weeks to arrive. You can also stop into a Coach boutique and ask the SAs for a replacement hangtag. They are usually very willing to help out customers with a free hangtag.
If you bought the bag or ebay or bonz don't tell them that, they hate ebay. Say you got it from a relative or something like that. Good luck!
I just contacted them by email and they are sending one right out to me, no questions asked, it was great! Thanks for the info!