Kids that age are in to doing nails so make or buy the little satin bags, a pack of colorful emory boards, a box of nail polish remover wipe packets the mini-size travel bottles of nail polish (sometimes they come in a 4 pack for a dollar or 2)and if you want to add something else, little travel size bottles of lotion. All can be picked up at Wal-mart or somewhere like that and make fun gifts.
You can also pick up little dollar store jewelry boxes and put varying amounts of cash ($1 to $5) or McDonald, arcade (or other popular place) gift certificates inside. Wrap each and let them do a game (not allowed to open the actual Jewelry Box to see what is inside) but decide if they want to keep the one they chose or change for someone elses (like a Chinese Auction) only by whether they like the outside of the jewelery box (or what ever type container). Then after all swaps are done they each get to open to see what is inside. It is just a fun way for each to take something home.
Another thing is to buy the beads and stuff for them to make key chains and let them make those at the party.
I have 5 girls...all grown now...and they always had fun with stuff like this and so did their friends.