Shopping isn't hard at all. I shop for a family of 3 with my bike and home made trailer. I used to use the child trailer but it doesn't hold much more than 75lbs. I found a shopping cart on the side of the road last spring. It had no identification on it so there was no way I could return it to the proper store. I had a buddy of mine stop at my house one day before work and put it in his truck to take to work for me (we work together). Once we got it to the shop I cut it down to size, added axles, and some old 16" wheels I snagged on garbage day. Then I fabricated a hitch mount system for my bike with a quick release.
So now when I go grocery shopping I have a full on cart to drag the groceries home, and boy can this thing hold alot. One day I'll take pics.