We do Little Adventure dresses. People sell them on websites and ebay. My DD loves them and doesn't care at all they're not "real" princess dresses. It is super lightweight (packs into ziplock bags) and machine washable, which is really good because she will wear it all day at the parks and at home ...
Funny story, although it hurt me to do it, the Aurora dress is long sleeved and my DD's current favorite princess is Aurora and really really wants to wear Aurora when we do BBB, next week, and she doesn't like the "itchy" dresses. So I cut the sleeves off, yikes! But I know she doesn't care, as long as she can wear it.
I feel a little cheap, bringing my own dress, but you know, my DD just prefers these dresses and will wear it all day, so that's more important.
-Virginia