I got mine on ebay, the per badge price was more, but the shipping was less, than gifts of a lifetime. The woman went into the parks and had my children's names engraved for me. I decided it was worth the $$ to either put them in Easter baskets or "present" them as we enter a park the first day.
I've read (here maybe) that you can also order them through Disney's mail-order merchandise service. This is the info posted over on the Theme Parks Attractions and Strategies board:
If you would like to place an order you may do so by calling
407-363-6200, by fax at 407-352-6369 or by e-mail with the following:
Item List, Name, Phone Number, Billing Address, Shipping Address and
Credit Card information with Expiration Date.