Carrying grocery bags home

I live very close to a supermarket, and I often go there to shop. When I buy heavy/bulky items, they are hard to take home, but it doesn't seem logical to drive there, because it is only 50m. How do I carry my shopping bags home with minimal strain and discomfort to my hands and shoulders?

I use a bicycle. You can dangle more bags from the handlebar than you could reasonably carry, and if you have a luggage rack you can put a box on the back with the heavy items in it. My setup involves about the biggest box that fits the rack (I secure it with two old inner tubes slung around the saddle post and the back of the bike rack or such), two panniers and a big duffle-like backpack. The backpack I use for bulky but light items like toilet paper, cereals and so on. The items in each container can be layered so that the delicate veggies, fruit and eggs end up on top so that they do not get damaged. I get the weekly shop home that way, typically even riding the 600m or so.

Because you can simply push the bike for short distances it does not even have to be ridable — it does not need brakes, a chain or pedals. Air in the tires would be nice. Such a wreck can be obtained very cheaply or for free. Having little value, it also can stay outside (still with a good lock though).

A bike has a number of advantages: Compared to a trolley or shopping cart, a bike has less trouble navigating a bumpy street surface. If you equip it with panniers, you can transport a lot of stuff together with a backpack, a box and bags dangling from the handle bars. Last not least, if it is ridable you'll be at the shop faster (if it's a bit farther than 50m), and with moderate loads you can bike back as well. Biking back and forth will make it altogether faster than both walking or taking the car, which you must typically park some distance away from both entrances.