I may be sticking my neck out here, but I don't think money is appropriate as a FE gift. THe idea is little treasures, not anything of real value.
For the 9-12 year olds, you're ok with Hannah Montana, etc. Definitely too young for teens.
The things my 17 year old liked were the mickey pencils and pens, the fake tattoo (yeah!), anything with a guitar theme (they're all into Guitar Hero and it is big in The Stack). She used the highlighter, but I can't say it was a favorite item. Someone did magnets with the cruise logo and dated on them. Many of them don't want to admit it, but classic Disney characters are a favorite...so anything with a classic character is good. Avoid the princesses (too little girl) or the newer characters (they'll either love or hate them). So...a pencil or pen with Mickey or Chip is great, Cinderella or Wall-E may not be.
Magnets that can be used on school lockers are good. A magnetized mirror was a major hit (and the woman who did it said she got them for 50 cents and decorated them!).
Think fun, not expensive!
I did separate "little kids" from adults and older kids when I did our FE. The "little kids" got a few more treasures. It's really up to whatever your FE group decided to do.