I started with 2 place mats I bought from a dollar store. Found some matching fabric for the inside and webbing for a handle. I cut two squares I'm the bottom 2 inches. I sandwich one inside with outside right sides facing inward.
Sew along the top to hold handles in place.
Iron the sides open. Place both sides of the bag together right sides facing.
Then the outside fabric sew all the way on the bottom. On the inside fabric leave an opening so you can pull the inside through. Take the corners and match up the lines. Ironing helps.
Through the opening, grab the bottom of bag and pull right side out.
Iron the top tight and stich across the top to look clean.
The measurements I used for the bag was 12 1/2 x10 1/2 the bag handle is 11 inches. I like to use a craft fuse interfacing. I like some stiffness to the bag.