Success! So my experiment with spun plarn is finished. Just to go over it again, this market bag is made out of old grocery bags cut into circles, looped together into a long ribbon, then spun using a drop spindle (plarn=plastic yarn). Then I just crocheted a simple mesh-style market bag using the plarn rather than yarn.
My 9 year old loves it. I have a funny feeling it’s getting stolen by her, since she’s already walked off with it. It’s all good!