You could take her and her friends to see and ride some horses. If she likes hello kitty throw her a party like that at home so you do not have to spend that much money on renting a place or getting everybody in a amusment park.
Girls at that age love being pampered. You could giver a makeover party or a manicure party! Talk to your local salons maybe they'll give you a package deal.
Have a birthday party at an indoor bounce house arena, such as Pump It Up and Leaping Lizards. Or you could have a lock in at an exercise club with a pool.