Super easy! Use up scraps! Ok, maybe not everyone has upholstery scraps on hand… but there are always remnants at the fabric store for cheeeep.
So, take a bag you like, or pick your own dimensions. It doesn’t have to fit a body part, so the pattern is easy to draft! Your rectangle should be twice the width you want plus two seam allowances, and the length you want, including half the bottom, plus extra for hemming the top and a seam allowance at the bottom.
Cut some strips for handles, these should be twice the width you want (no S.A. this time), and as long as you want them, with some overlap to sew them to the bag.
Fold the strap sides in to the middle, as shown, and zig-zag down the center. I also added some straight stitches down the sides, for insurance I guess.
I like to finish the edges of the main bag with zig-zag so it doesn’t fray. Fold the big piece in half and stitch across the bottom & up the side.
Open up the seam allowance, fold over the top, and sort of finger-press in place. Decide where you want the handles, and pin them in place. Sew around the top, which will sew the handles down at their bases, then reinforce the handles however you’d like– I did a square-with-X kind of thing, but really two lines of straight stitching would be sufficient.
Now for the bottom of the bag– obviously this is for a “box” type bottom, but if you don’t want to futz with this then you’re done. On the inside, open up the bottom seam allowance and press it up against the side of the bag. This is easiest on the side that has a seam, but you can always find the right line on the other side by laying it flat and marking that spot with a pin.
If the seams along these corners are short, it’s pretty easy to eyeball a straight line, but if you’re sewing a larger bag you’ll want to measure to make sure the lines are straight and even.
If you want, snip the corners and finish the raw edges, and that’s it.
Lining up the corners and sewing the flat bottom is the most time-consuming part, so if you leave that off, it’s a really short project!