The only thing we have been able to piece together from our vague recollections is that it has a princess who is asking for impossible dresses to delay getting married or something. (One of them was a "sun dress" - dress made from sunlight?) And the suitor (?) keeps fulfilling each wish.
I can't think of how to google this because if your search terms include "fairytale", "princess" and "dress" you get everything from Disney weddings to dolls and not very many actual fairytales.
I know this is very vague but I hope someone can help!
EDIT: THANK YOU SO MUCH, EVERYONE!! I have forwarded the answers to my friend (who was *very* grateful). I think the story I was thinkin of was "Donkeyskin", let's see if hers was the same!