Looking for "genie" costume pants

My kids are going to be in an Aladin type play, and I need to find some pants for them that fit that style of clothing.  My girls are size 8 and 12.   I could also use an adult women's size (about) 8 pant for my oldest.  I thought I'd ask before I break out the sewing machine and have to start asking for help there.  Erin S.