This year I am helping with a T-Shirt Bag class for the teens, not limited to girls but I imagine that most teen guys won't want to make a 'purse'.
So...in preparation for the class, Sarah made a bag following my directions and we took over 50 photos to document the steps. I made a bag for myself the next day and added pockets to mine and made my straps different. I've been using mine for several days and while there are more ways I could personalize it to my criteria, it is doing very well.
The whole bag is made using duct tape, staples and the Tee.
Supplies all laid out.
Tee folded in half, neckline marked.
The sleeve and neckline openings will become the straps.
Everything cut away. If you want to add an iron-on or other decorative touches, do it now.
Once the duct tape is on it is very hard to sew through and you can't iron duct tape with good results.
Laying down the duct tape bag lining.
Stapling the bottom seam.
Stapling the side seam at the bottom. This will give the bag a flat bottom, but is something you can skip if you like. I like my bags with flat bottoms and lots of pockets.
Inside view of the finished bag.
For size comparison. Sarah is about 5'8" and she used a lg Tee.