I have a friend that has a bob trailer and he steered me to a garage sale that had a schwinn joyrider child trailer and so I snag it and now use it for grocery shopping, twice so far and I really like it so much better than using the pannier bag.

I notice that I can hold quite a load at least three bags full of food and then let the top collaspe over the food reduce wind drag, rather then leave it up full expansion. I also like how the driver behind me tend to give me more space.

I can unhitch the trailer and wheeled it around the store like a shopping cart. although its a bit wider then a grocery cart, so I had to be carefull not to clip anyone in the ankle. I cant wait to go shopping again! Now all I need is a wife and two kids and i'm off with the trailer! I recommend the trailer over the pannier bags anyday. I have so much better control over the bike with a trailer.