where should i go...?

shopping for flower girl dresses? I made the mistake of buying a flower girl dress for my lil FG and I apparently thiught she was smaller than she was.
Anway I told the mom (my cuz) and she said 'OHHH i wanted to go shopping with you to buy her the dress!!' okay no prob but where should i take her to look and not have the dresses be so expensive.
ps i already did burlington and had to return that dress and they dont have her size! so keep suggestions coming