if you're a kid, vouchers to do her chores works nicely. free, just a smidge annoying and a bit of your time when she uses them.
if you're older, you could go for gag gifts (vibrator, like someone suggested), or if you're not that comfortable w/ that stuff, get her a stuffed-whatever she finds cute.
Gifts doesn't need to be expensive. They just need to show that you put some amount of thought into it.