Wow - these have certainly gone up - I got them for my girls in March 2002 at MGM, and they were around $6. Also, the CM's badges were white, with a red line around the outside, while my girls were red or blue with Pooh, Mickey etc. on them. My middle daughter spells her name in an unusual way - and she was so excited that they engrave them right there!
We found that they added a bit of magic to the trip - the CM's gave them trading pins, etc., because they knew my girls were big Disney girls!