Expensive birthday gift, do you go with the flow or just say "no"?

Do you go with the flow or just say “no”? If a member of your attached family like a niece has a birthday coming and she is hinting to different members of what she wants; to one she is hinting for a designer “little black dress”, to another a pair of designer sling back pumps, and to you a designer clutch purse. You try to reason with the others that a 15 year old does not need to have an expensive designer outfit; what for? To spend $212 on a dress, $130 on pimps, and $180 clutch is excessive, tight? You can get much more practical things for that money. But the others say you only have a 15th birthday once and gifts are supposed to be about fun and enjoyment and not practicality as if a nice laptop can’t be fun. They are on board to make her wish come true and they are counting on you to go alone as to “complete” the outfit. Do you go alone in spite the fact you think it is silly or use the money and get her something like a nice digital camera, a bike, camcorder, or something she could use for years to come if she took care of it?