Well, my DD15 LOVES Tinkerbell! They have some really cute vintage-looking t-shirts at Wal-Mart. They are really soft and form-fitting like all the teen gals like! Other things that I am doing as her "Tinkerbell Gifts" (got a DS8 & DD5 as well) are:
Tink light-up pen & notebook to use as a vacation journal (Big Lots)
glo bracelets & star-shaped wand (Dollar Tree)
Pressed Penny Album (internet)..she's been collecting for years!
a couple of pins
This past March, we went and she made one of those "build-a-crown" and wore it EVERYWHERE at WDW. We did hers at Tinkerbell's Treasures store right by the castle. You can pick little jewels and things...very cute!
Good luck and have fun!
jd
Do they have cell phones or iPods? I know there are some cute phone accessories (covers, charms, wrist straps) out there, both homemade and licensed, for those kinds of things. How about sunglasses, socks, jammies or even underwear?
What time of the year are they going? I am doing a "mom & daughter" trip this week with my 13 yr old daughter and in her bag of goodies I got a mister - of course, we are expecting the weather to be in the high 80's to low 90's so it's appropriate, but not so much for cooler temps.
Disney dollars always works! Gift certificates for dinner. Jewelry. Writting pens and pads of paper. Gum. Mints. Disposable camare. 4X6 photo album. T-shirts (matching ofcourse LOL). Sounds like fun!