what king of gift should i give to teenage girl? (for my grand daughter)?

I think clothes, shirt maybe

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Her own domain name. Make it a "summer fun project" - she can learn now to build a website, etc.

Yeah I agree with the other guy, a cellphone. If she doesn't have one already and you don't really want her to be billed every month, get her a pre-paid phone. See what her other family members and friends have, like verizon, cingular, sprint or what b/c most pre paids let you speak mobile- to -mobile free, so get her what every most of her family and friends have. If she already has a phone get her another one (a cool one with some neat features) and just get her number switched over. You can never go wrong with a cell phone

a gift card for a teen clothes shop (like american eagle, aeropostale, hollister...)

that way is the easiest cuz if you buy clothes there's always a problem about returning it if she doesnt like it =)

if she's older girl give her a car thats the best thing in the world!1

deffinitly get her a gift card to Abercromie or if she reads to Barnes and Noble

A card to get her nails done.

Visa gift card - she can use it anywhere.

A spa day or gift card for shopping.