Bridesmaids Dresses

I'm being totally bipolar about the bridesmaid dresses...so instead of telling them exactly what to wear...I'm thinking about letting everyone pick their own style of dress...as long as its from David's Bridal, its navy and its satin...good idea? I'd still pay the same amount for the dress...$40 regardless of how much their dress cost...but I think it'd be a cute idea...let me know what you think!!!