LO is going to be a flower girl in my sister's wedding in July. I'm free to pick out whatever dress I want as long as it fits her colors. Actually she just said it has to be cute, but I'm still sticking to her colors: blue, yellow, or white. I don't want anything too expensive, any ideas on where to look?

Also, when should I buy it? I have no idea how big she'll be 4 months from now!