...Or, "It's amazing what you can do when you don't know you can't."  ;D I actually did the jeans bag. First, I oiled and cleaned the machine and put in a heavy-duty needle!

Then, take a pair of adult jeans (old ones or go to thrift store or beg them off someone). Cut up the inseams, cutting OFF the flat-felled seam, because it's 4 layers and a nightmare to sew through. Remove the little square "knot" where the crotch seam comes together with the inseam. Leave the "body" of the jeans intact (where the fly, pockets and seat are.)

Decide how deep you want your bag to be, measuring down from the waist, and cut the legs off at that point. This will leave you with 2 flat pieces of leg material. Cut one of these 2 at the remaining seam, to get 2 rectangles of cloth. These are used as gussets.

Lay the cut-down jean body on a table with the fly and waist button facing up, smooth out flat, and place the "gusset" material in the triangular gap of the top layer that you can see, right side toward you. Make sure the gusset material is pretty much centred in the space. Now, all you have to do is turn the raw edges of the "body" under and pin in place. Machine stitch, using strong thread (I used navy blue quilting thread). Turn material so wrong side faces you, and cut away the excess gusset material, leaving about 1/2 inch seam margen, which you can overcast if you're in the mood. Repeat this gusset process for the "seat" of the jeans.

To make handles, use the leftover leg material. Decide how long you want the handles to be and cut the material that length, and double the desired width. Fold with right sides together and seam up the long end; use a pencil or similar to turn the resulting tube right-side-out. Tuck raw edges under and seam in place like "suspenders", one end on the front waistband, the other on the back. Repeat for the other handle.

Now, if you're a good sewer and/or a perfectionist, you can figure out a way to set in a square or oblong bottom to the bag. I am neither gifted nor patient, so I turned the bag inside out and simply trimmed it straight across and sewed a seam to close the opening.

The pockets are great for change, keys etc. If you want a novel touch, thread a belt through the loops to serve as a drawstring.

The first one I made came out a little "found art"--but cost me nothing more than a little time and effort.

The second one, I made from a child's denim sundress I found abandoned; the spaghetti-straps tied at the breast and, judiciously re-knotted, served as handles, so I only had to sew the bottom of the skirt closed. The zipper down the back doesn't show!