I am with Bleeker on this. Bags are not necessary. Half the kids will forget them anyway and then you will be left with even more junk to stow or throw!
I shudder to think of all the useless shaped erasers I have tossed. Those round decorated pencils...always donated them to my church...but never to be used in my Sunday School, GA or AWANA class...they constantly roll off the table!

As for a iTunes card less than $5, I don't think there is such an animal. I have sons ages 17 and 19 and iTune cards flow through here often.

Making something that coordinates with your donation theme sounds like a winner. Just call the organization first and run your idea by them. It would be a shame if their work was thrown away because of a rule violation.

Have a great "tween" party!