Breakfast, lunch, or dinner at Ariel's, a character meal with princesses. Tell them it's her birthday, and snag a birthday button (saying "pin" makes it seem it's like the trading pins you buy, but it's more like a "campaign" button, LOL) for her to wear that day.
My hubby got me the "princess bucket" and really, well, maybe for a 3 year old it would be good, but that's nearly the only age it's good for. Has a slippery satiny ribbon that kept slipping out of the loops and falling. Contained a sheet of princess magnets like paper dolls. Birthday pin with a few princesses on it. And a baby comb and brush ("baby" b/c that's the ONLY kind of hair it could get through, babyfine baby or toddler hair) all pink and sparkly. And a nasty cake that my then 2 year old liked, but it really was very nasty.
I personally would just rather buy a proper birthday present, rather than a bucket that you'll probalby have to carry, ya know? A nice plush, a fun princess meal, and the attention she'll get from everyone wishing her a good birthday...
OH, and getting her an AP for her b'day would be fun, too! My guy was a few months over 3 when we got his (when we went after he turned 3), but he understood that it was special b/c he hadn't needed a ticket before, and that it meant many visits to Disney in the next year!