I was born in one and lived in it for about 15-17 years.
I have a big, recomposed family. They've been living as a commune for more than 35 years now. It's a farm surrounded by lots of nature. When I was little they were living very much off what they used to produce themselves. Now they've gotten a bit wealthier and also have more money exchanges with the outside world. They still function as a commune though. The money and food are shared equally, the cars are shared, the work is shared and planned together, there is no boss, they eat together every day at lunch, partly because this is convenient to plan and discuss everything, partly because it is nice, and so on. We also had guests who stayed there and helped out in return - one of them even stayed for eight years!
*cough* I don't want to disappoint you, but even if you eat only veggies from the garden, you'll need some objects from the outside world. There are also bills to pay, water, electricity, taxes, house maintenance, cars maintenance, insurances, doctors, school for the kids, and so on. Someone has to pay for all that. If you're just a "guest" and help out in return for staying there, you won't have this responsibility, but if you get involved long-term, it becomes yours too.
Also, farmer's work is hard work. You need to work physically and to get your butt out no matter the weather. Nature does not wait. If you think you can just lay around lazily and go to the garden pick a few tomatoes from time to time, you're wrong.
On a social level, communes are challenging. You need excellent communication and interpersonal skills. There are tensions, power struggles, jealousies, there are important decisions to make together and lots of conflicts that you need to deal with. I'm not saying it's all bad. It certainly is a great way of living, it's very nice and I love it. Just don't fool yourself into thinking it is easy. But it's certainly great for your personal development.
Hope this helps.
