What you needAn old T-shirt
Sewing Machine and thread
Extra fabric, about the size of a tee shirt (both layers)
Cut out a square or rectangle of the front and back of the tee shirt (of the same size), leaving at least 4 inches on the bottom for the handles (cut leaving extra in one strip). Measure and cut your extra fabric in the same shape and size as your T-shirt, cutting equal fabric for the front and back.
Sew the front of your T-shirt to the square of fabric so that the patterns are facing out (sew around the outside of the squares, simply to hold them together). Repeat on the back scrap of the T-shirt and last piece of fabric.
Now put the two pieces of fabric you just sewed together with the designs facing each other (on the inside). Sew around the outside of the fabric, just like you did last time, leaving the whole top side un-sewn and about at inch at the top of the left and right side of the fabric un-sewn. Fold down the top and pin, then sew across to make a clean edge (on both sides). Then finish sewing the corner.
To attach the handles, you can use ribbon or cut the remaining scrap of T-shirt in half to leave two 2-inch strips. Double up, and sew handles for a stronger handle, then attach by sewing two horizontal lines through each handle on the purse, on each side of the bag (eventually, sewing a straight line 8 times).