I have been shopping at my local (Collingswood, NJ) farmer's market for ten years. For as long as it's been in existence. During the months that the market is open (May through November) I do nearly all of my food shopping there. Because I do that much shopping there I have had to come up with a way of being able to carry everything I buy. I do go back to the car (or send a daughter) when we simply have too much to carry. Remember...corn is heavy, tomatoes are delicate...one cannot simply dump everything into one bag or cart.
First I took one of those box on wheels things. It's the size of a file box and folds flat. Easy in the car. Not really big enough.
Next I had one of those nice big metal grocery basket carts that you see older women pulling behind them in the city. I like those. But they just can't keep up with me! I've gone through three of them. Now, three doesn't seem so bad but they usually break by a wheel coming off. And a wheel coming off in the middle of a market shopping experience is not a performance you continually want repeated. They have sturdier market carts at the Container Store but they're smaller than I need and four times the cost. Smaller actually being the main problem.
This year I bought one of those beach carts. They kind that you can put everything you need for the beach....umbrella, chairs, cooler, towels, etc. The wheel broke on the first outing. Husband fixed it but suggested I not use it for market shopping. So it's in the shed waiting for a trip down the shore.
Finally, I bought a wagon. Now, remember, I drive to the market so I have to have a small "cart" or it has to fold. Ready. This is a foldable wagon. I bought it at Costco...but I've seen them at BJs. It was only $50. It holds everything. Is easy to steer and easy to fold up and store...in the car and in the shed. I have been stopped numerous times in the three weeks I've used this to answer questions about it and where to get one.