Not sure how much they cost at Disney. I've bought them on Ebay from $5 to $20. Mine was $5. My DS 6 was $6 and my DD8 was $20 (she has a rare French name and I was amazed to find it - it came from DL Paris).
You might find them on ebay. I can't find one for my DS 10 even though he has a common name. Its just not available for sale. Of course, the week after I get back, there will be one with his name available on ebay - murphy's law.