One side of this shopping bag's support cracked so I solved the problem by replacing it with some right angle extruded aluminum I had lying around. I added a draft angle to make sure the clips stayed snug on the aluminum (you can put the clips in 65 Deg C water while on the aluminum if you really want to cement it on (this causes very slight shrinkage of the PLA and locks the clip in place). If you don't have the same bag you can sew your own or add a pocket to one you already have. The clips allow you to stretch a shopping bag open in the cart so you can easily pack it before you leave the store. I'll post pics of it at work next time I go shopping.
I made this for an aldi grocery bag but it will work on lots of similar bags or just one you make yourself. I'm fairly certain this is orders of magnitude stronger than the originals (the black side, 3d prints are blue with white painted aluminum.

**SolidWorks Files included so you can adjust it to the materials you have.****

DO NOT FORGET TO MIRROR FOR THE OTHER SIDE!!!!!