Start with a sturdy felt fabric. Using a color that mocks that of the classic brown bag, makes for a whimsical surprise.
1) Cut into 12" by 14" panels (2 panels = 1 bag).
2) Pair 2 panels together and cut 2 1/5 x 2 1/5 notches out of each side.
3) sew the left, right, and bottom strip. leave the cut outs unsewn.
Optional: using pinking shears cut along of the full end (what will be the top of the bag)
4) Pinch together the cut outs sewing a straight light attaching the corner of your bag.
Repeat on the opposite corner, finishing your bag!
Felt stick on letters like the ones I used here, are easy applied and personalize the bag.
Enjoy your green, brown lunch bag!
A great tutorial at Skip to my Lou using oil cloth.