Robe material for a child's costume

My daughter wants a Jedi costume, complete with a robe like Obi-Wan's, to be able to wear at Gen Con this year. Being that she is 8, I REALLY don't want to spend a lot of money on something she will outgrow. I have a pretty good costume going so far, but am stuck at the robe. I absolutely do not want to get a robe from a Halloween costume, I'd prefer to sew it myself. I have found great suggestions as to what fabric works for adult robes, but I am hoping to find a good idea for a relatively inexpensive fabric for a kid. Thanks!

 

Maybe try a heavy bottomweight? It won't be wool but it should still be not too expensive and look good.

 

Thanks, that really helped! I couldn't find the really heavy broadcloth in the color I was looking for, but found a sufficiently heavy one in the perfect color. I think it being a little lighter weight will be helpful since it is summer.